312 
GEOLOGY OF THE SECOND DISTRICT, 
same orders, and animals adapted to the same state and conditions generally, as in subsequent 
periods, and even as now prevail. 
The most common genera of the calciferous sandrock are Orthis and Strophomena, both 
being abundant among the lower layers. They are the genera which figure so largely in the 
oldest fossiliferous system, running up to the old redsandstone. Some of the common fossils 
are given in the annexed figure ; and though among the oldest inhabitants of the globe, they 
resemble some of the common species of our own period; and should they be presented to 
any palseontologist ignorant of the position which they occupy, he would place them in or 
above the carboniferous system. We find, therefore, that general form and modern look can¬ 
not be trusted in deciding the age or era of fossils. In these older rocks, I have little doubt 
but a careful search will bring out a much greater number of species ; and this I am war¬ 
ranted in saying, from the presence of many fragments of fossil bodies with those which are 
already discovered. 
84. 
1. Scalites angulatus. 3. Maclurea striatus. 5. Orthis (n. s.) 
2. Maclurea labiatus. 4. Bellerophon sulcatinus. 6. Orbieula (n. s.) 
The strata forming the calciferous sandrock at Chazy possess each a few characters worthy 
of a moment’s attention. The first and lowest stratum furnishes the usual characters of this 
rock in other places, namely, the same mixture of siliceous, calcareous and other earthy 
materials, interspersed with distinct sparry masses : these are among the most constant cha¬ 
racters which the rock reveals. Where the fossils begin to appear, they are small and obscure; 
