here for some years, both by Schonbein and Moffatt's method, for the sake of comparison, but the difference was found so small as not to affect the computations and general results; and the observations are now confined to those of Schonbein, and as being the form more generally adopted, more especially on the Continent of Europe. The test papers require to be moistened with water to bring out the colour. The strips of ozonized paper may be laid in a shallow vessel of water for this purpose, and the ratio of shade or colour is easily estimated.

Exposure causes the ozonized paper to become at first of a pale straw colour, which increases to the tint of dried leaves, then deep brown, or dark violet, approaching to black, which becomes blue by wetting, or should there be a great amount of moisture in the atmosphere, it at once attains its blue colour, which becomes brown as it dries; but the blue colour may again be brought out by moisture, or re-wetting: this may be owing to the formation of a new quantity of the iodide of starch. It will be necessary in pursuing observations, that care should be taken in the preparation of the ozone paper, and that the prepared paper should be placed in a situation near the instruments that are used for observing the atmospheric changes; and it would be well, while carrying out these experiments, that slips of paper should also be placed in different situations, from which might be drawn useful inferences and comparisons. Five feet from the surface of the soil have been adopted here as the standard altitude, being sufficiently removed from the effects of terrestrial radiation and moisture, and of a convenient height; but observations are also taken at the surface, placed among plants, over drains, in the sick-chamber, and in other localities, and such observations would seem of great interest towards the due investigation of the effects and properties of ozone on the health of individuals and of plants. Observations have been also recorded here, shewing the effects of the different coloured rays of light, and also polarized light, on the amount of ozone, and also the effects of germination on its development.

It would also be well to pay especial attention to the amount before, during, and after thunderstorms, and also after any great display of the Aurora Borealis, to establish if possible any connections it may have with the amount of atmospheric electricity. It should also be particularly observed during the prevalence of any epidemic, and also during any "blight" or defective vegetation; and, when convenient, it would be advisable to shew the

hourly amount by means of a very simple apparatus, moved by an ordinary clock at the rate of 1 inch per hour. The ozone-test thus constructed consists of strips of calico, about an inch wide, moving over a slit in a closed box, so that the time of the greatest amount is thus indicated, and may be compared with advantage with the diurnal changes in the atmosphere, as indicated by the barometer's oscillations, temperature, moisture, and the direction and changes of the wind; and I am led to believe that this method is the only one which will ever give decided results, by thus making time an element of the observations.

[To be continued.]

ART. XXVII-Fossils of the Calciferous Sandrock, including those of a deposit of white limestone at Mingan, supposed to belong to the formation. By E. BILLINGS.

(Extracted from the Report of the Geological Survey of Canada for 1858-1859.)

The following paper contains notices of all the species of organic remains that have been collected in Canada up to the present date from the Calciferous Sandrock, including a deposit of white limestone, supposed to belong to the formation. This white limestone has been observed only at the Mingan Islands, where it overlies the Calciferous Sandrock, and is in its turn overlaid by the Chazy. Twelve species have been collected in this rock, and of these, only three occur in the true Calciferous Sandrock, but none of them have yet been found in the Chazy.

Of the forty-one species noticed in this paper, none have been clearly identified with those of the Chazy or any more recent formation, although several of them, such as Eunema prisca, Pleurotomaria calcifera and P. Laurentina are closely allied to species of the Black River limestone. It is not certain that the siphuncles I have referred to Orthoceras multicameratum, belong to that species. Future discoveries may possibly prove to the contrary, but, according to our present knowledge, the fauna of the Calciferous Sandrock in Canada is almost entirely distinct specifically from that of the Chazy.

ZOOPHYTA.

PETRAIA MINGANENSIS.

At Romain's Island, one of the Mingan Islands, several fossils have been collected, which appear to be casts of the interior of the cup of a large species of Petraia. The specimens are cylindrical, obtusely pointed, and slightly curved at one end. They are deeply striated longitudinally as if by the sharp edges of the radiating lamella of a coral of the genus Petraia. There are from five to seven striæ in the width of three lines, and therefore, in a specimen one inch and-a-half in diameter, there must have been about one hundred and twenty radiating septa. They appear to be the casts of the interior of a coral, in which the cup extended nearly to the base. In Petraia profunda, (Conrad) the characteristic species of the Black River limestone, we have an analagous form in which the depth of the visceral cavity is nearly equal to the total length of the coral. Although it is not yet quite certain that these fossils are the casts of corals, yet, as their form and so much of the structure as is indicated by the markings of the surface render it highly probable that such are their relations, I shall provisionally place them in the genus Patraia.

The specimens to which the above description refers are from three to seven inches in length, and about one inch and a balf in diameter, but there are fragments that must have belonged to individuals at least two feet long and more than three inches in diiameter.

Locality and Formation.-Mingan Islands in the Gulf of the St. Lawrence, Calciferous Sand-rock.

Collectors.-Sir W. E. Logan and J. Richardson.

STENOPORA FIBROSA (Goldfuss, sp.)

Small cylindrical stems, several inches in length, and from three to five lines in diameter. They are, I have no doubt, specimens of Stenopora fibrosa, although I have not been able, as yet, to detect the cells. They are replaced by chert.

Locality and formation.-Mingnan Islands, Calciferous Sandrock.

Collectors.-Sir W. E. Logan, J. Richardson.

*This species has been heretofore called Monticulipora dendrosa by me. On comparison I do not think we can distinguish it from Stenopora fibrosa, the European form. It is the branched variety of Chatetes lycoperdon figured in the Palæontology of New York.

CRINODIDEÆ.

Fig. 1-m-n.

A fragment of a crinoidal column, two lines in diameter, composed of thin joints, of which there are six in two lines. The joints vary slightly in thickness alternately, and the edges of the thicker ones project a little, so that the column is not smooth, but annulated. The central canal is obscurely pentagonal, or nearly circular. See Fig, 1-m, n.

Locality and formation.-Mingan Island, Calciferous Sandrock. Collectors.-Sir W. E. Logan, J. Richardson.

n

Transverse section of L. Lyelli.

Young specimen of L. Lyelli.

Transverse section.

e-f Lingula Mantelli.

Orthis grandava, ventral valve.

g

k-o Crinoidal columns.

Fig. 1-0.

A Column two lines in diameter, composed of large and small joints, the former thin and widely projecting as in that portion of the Glyptocrinus ramulosus, which is next to the cupI think that this is the column of a species of Glyptocrinus. See Fig. 1-0.

Locality and formation.-Mingan Islands, Calciferous Sandrock.

Collectors.-Sir W. E. Logan, J. Richardson.

Fig. 1-k, l.

A smooth circular column, three lines in diameter, composed of thin equal joints, of which there are ten in three lines. The central canal is trilobed. See Fig. 1-k, l.de

Locality and formation.—Mingan Island, Calciferous Sandrock.

Collectors.-Sir W. E. Logan, J. Richardson.

These fragments indicate three species of Crinoidea, and they are probably distinct from those that occur in the Chazy or any other overlying formation.

Description.-Elongate oval or sub-pentagonal; front margin straight or gently convex; sides nearly straight and parallel in the lower two-thirds of the length, above which they converge and meet at the beak at an angle of about forty-five degrees. Both valves are moderately, but not regularly convex, there being a flat triangular space extending from the beak along the centre to the front, and a similar flat space on each side sloping to the lateral margins, and thus each valve is composed, as it were, of three plane surfaces. In the small specimens these planes are not so distinctly indicated as they are in the large ones. The surface is marked with fine concentric lines, and also with longitudinal radiating striæ, the latter being scarcely visible except when the shell is partly exfoliated. Length of large specimens, thirteen lines, width about half the length.

This species is closely allied to L. parallela, (Phillips)* but has not, so far as we can judge from the inspection of a single figure, so obtuse a beak. The size and proportions are the same as those of L. ovata, (Mr. Coy) but in that species the longitudinal radiating striæ curve outwards, so as to cut the lateral margins nearly at right angles, while in this they are straight, and thus, form acute angles with the edges of the shell.

This species is dedicated to the distinguished geologist and philosopher, Sir Charles Lyell.

Locality and formation.-Alumette Island, Calciferous Sand

rock.

Collector.-Sir W. E. Logan.

* Memoirs of the Geological Survey G. B., vol. 2, part 1, page 370, pl. 26, fig. 1.

Mr. Coy. British Paleozoic Fossils, page 255, pl. 1 L, fig. 6. L. ovata appears to be a Lower, and L. parallela an Upper Silurian species.