Page:The Habitat of the Eurypterida.djvu/183

Rh have yielded Cephalaspis lyelli, Pteraspis mitchelli, and certain of the Acanthodian fishes. At a slightly higher horizon and contemporary with some of the volcanic beds is the Acanthodian zone which is best seen at Tilliewhamland Quarry, Turin Hill, near the town of Forfar. The list of fossils from these beds cited by Goodchild is as follows (80, 507):


 * Mesacanthus mitchelli
 * Ischnacanthus gracilis
 * Climatius scutiger
 * C. uncinatus
 * C. reticulatus
 * Parexus recurvus
 * P. falcatus
 * Euthacanthus mitchelli
 * E. elegans
 * E. gracilis
 * E. curtus
 * Cephalaspis pagei
 * C. asper
 * Thelodus pagei
 * Pterygotus anglicus
 * Stylonurus ensiformis
 * Parka decipiens

Just above the top of the volcanic series has been found a fossiliferous zone yielding myriopods among which are Kampecaris and Archidesmus, as well as some poorly preserved plants referred to Psilophytum robustum. The top of the Caledonian Old Red is formed by the Strathmore sandstones which are well developed in the Strathmore lowland of Forfar, but the exact age of which is difficult to determine because of the lack of fossils. It has been thought that they might be contemporaneous with the oldest beds of the Orcadian division, but conclusive evidence is lacking.

The Siluric Stonehaven beds of red sandstone and interbedded bright red shales are exposed in the neighborhood of Stonehaven and are about 1500 feet thick. Upon these follows the Dunnottar conglomerate, 5000 feet thick, of coarse red and grey sandstones, grits and conglomerates in which occur pebbles which commonly "range up to a foot or more in length, and yet are astonishingly well rounded. They mostly consist of quartzite" (117, 399). Interbedded lavas