Page:The Habitat of the Eurypterida.djvu/37

  dewalquei, Eurypterus, Spirorbis. Mr. Destinez found a beautiful Ichthyolite which is probably new. We cite again: lamellibranchs, lingulas, ferns and Lepidodendron. That bed contains sometimes thin layers of sandstones, on which one finds associated on the same planes of stratification lingulas, lamellibranchs, ferns, and ganoid scales. Mr. I. Braconier has collected excellent specimens which demonstrate the certainty of this fact. . . ..

"In beds F, G, H, I, we have not collected any determinable fossils; but in the lower part of bed J we have found vegetal matter, scales of the fish, Holoptychius inflexus, a small species of Pterichthys and the remains of a Dipterus as I have pointed out." (Fraipont, 68, 55).

A little lower in the series in bed B impressions have been found which suggest those of rain-drops, also very numerous axes of vegetal matter probably, as suggested by Mr. Mourlon, stipes of the fern Palaeopteris hibernica, and in the same bed Mr. Destinez found a large bone, belonging apparently to a fish.

. Upper Siluric of Gotland. The Baltic Isles have long been famous for their Siluric sections which are so excellently shown on Gotland. The lowest eurypterid horizon is found in the Pterygotus marl of Gotland of Upper Siluric age. Although the sections in the northern and southern parts of the island have been studied separately and the correlations are not as yet complete, still one important fact has stood out for the whole island: there is everywhere a great break between the Lower and Upper Gotlandian (Siluric), indicating in many places that there was at this time a retreat and a subsequent advance of the sea. In the north around Visby, Hedström (113) has recognized seven subdivisions of the Gotlandian. Beginning at the base, the first bed to be shown along the shore is the Stricklandia marl (I of Hedström), with Palæocyclus as the characteristic fossil. Then follows II, a marly limestone showing reef masses at intervals and containing a Niagaran fauna. The succeeding beds (III) are of particular interest to us. At the base are 3 meters of yellowish grey limestone with crinoids, and then follow 16 meters of grey marls interstratified with limestone, the upper 5 meters of which consist of stratified limestones, oolitic at the base, but becoming gradually coarser towards the top where they are conglomeratic, and where