Page:The Habitat of the Eurypterida.djvu/43



. About a third of the way south from Porto to Lisbon and about 40 km. in from the coast lies Bussaco, famous for its Carboniferous rocks and the abundant flora therein. This region was studied as long ago as 1850 by Carlos Ribeiro. Three years later a symposium on the sections and fossils of Bussaco appeared in the Quarterly Journal of the Geological Society of London, and then in 1890 Wenceslau de Lima made a very complete study of the region, with the result that, after a careful identification of the flora, he was able to show that certain of the beds are Permic in age, belonging to the lower Rothliegende. During his investigations he found a single small eurypterid, the cephalon, body segments and telson intact, though all of the appendages are missing. The animal measures 32.5 mm. in length, has a large cephalon, a bulging body made up of seven somites and a long tail formed by the last seven segments. To this form he gave the name Eurypterus douvillei. Associated with this eurypterid are the plants Walchia piriformis and Sphenophyllum thoni. The beds in which these fossils are found are a series of shales, sandstones and conglomerates from the abundance of which de Lima argues that torrential conditions must have obtained at the end of the Carbonic and beginning of the Permic (149, 151). A glance at Koken's world map showing the relation of land to sea during the Permic will show that Bussaco was in position to receive very heavy torrential deposits, being near the coast of that time.

All of the data of the foregoing pages are summarized in the following series of tables. Table I is designed to show quickly in what horizons and country any species of eurypterid has been found. Table II, summarizing Table I, gives at a glance the numbers of species that are recorded from each horizon and from each country and also from each period. Table III gives in greater detail the localities in which remains have been found, but is particularly meant to give an accurate description of the mode of occurrence of every species, if the remains are fragmentary, to state how many fragments have been found, and if perfect to record with equal care the numbers found. Each table is complete in itself, but all three, on the other hand, should be used together since each one supplements the others.