Page:Quarterly Journal of the Geological Society of London, vol. 26.djvu/654

472 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Apr. 27, small unconformable patches in Cape Breton of Triassic age, and regarded them as the continuation of the Prince-Edward- Island series, resting on Lower Carboniferous rocks.

In the accompanying map (fig. 1) the regular sequence is shown between the Upper Silurian and the Laurentian ; and the entire series from the Lower Carboniferous, with the exception of the Devonian, is passed over in a journey by rail from Windsor to Halifax, in a distance of fourteen miles. The Devonian occurs at Nictau, and rests there on Upper Silurian slates*, which probably sweep round the Falmouth mountains, and connect with the Upper Silurian shown on the Map.

III. Sequence of Formations†.

The Upper Silurian. — On the St. Croix river, eight miles from Windsor, the Lower Carboniferous grits are seen to rest on supposed Upper Silurian argillites. The grits dip N. 60° W. 5° : the argillites S. 70° E. 50°. The argillites are generally very fine-grained, green internally, but weathering red ; they are interstratified with thin beds of quartzites, and have a breadth, near the railway, of 170 chains, their dip being tolerably uniform, and no repetitions visible ; their thickness may approach 9000 feet.

The argillites resemble in every particular argillites seen on the Tobique, in New Brunswick (fig. 6), and there associated with thin calcareous beds holding Favosites gothlandica. These are described in my Report on New Brunswick‡.

Towards the upper portion of the series the argillites are conformably succeeded by bluish-black slates, holding cubical crystals of iron pyrites, and resembling roofing-slates. A similar change occurs on the Tobique, in New Brunswick. These bluish-black slates are exposed to a great extent on the Ardoise hill-range, Nova Scotia.

The Lower Silurian. — A good exposure of the supposed blue-black Upper Silurian slates is visible at the thirteenth telegraph-post south of Ellerhouse station, on the Halifax and Windsor Railway, dipping S. 20° E. ; and at the thirty-eighth telegraph-post brilliant micaceous schists, with black corrugated slates, dip N. 40° E., the intermediate space being covered with boulder-drift §. The brilliant micaceous schists, as well as corrugated slates, are much contorted, and overlie conformably the gold-bearing quartzite series.

The micaceous schists and the corrugated black slates cannot be distinguished from similar schists and slates described in my New-


 * Dawson's 'Acadian Geology,' 2nd edition, p. 498.

† In the 'Journal of the Geological Society' for 1862 (No. 72) there is a paper " On the Geology of the Gold-fields of Nova Scotia," by Dr. Honeyman, with a sketch map of a part of Nova Scotia between Halifax and Windsor.

‡ Page 131.

§ In the absence of fossils the rocks in the preceding paragraphs are regarded as Upper Silurian, the difference between them and the strata next described being considerable ; nevertheless, actual contact not having been seen, they may be a recurrence of the Lower Silurian beds on the other side of a great synclinal fold, and less altered than those in closer proximity to the gneiss.