XII.— Morgan Expeditions, 1870-71: On the Devonian 
Trilobites and Mollusks of Ereré, Province 
Of Lard,  bracil, 
By CH. FRED. HARTT, 
Prof. of Geology in Cornell University, 
AND 
RICHARD RATHBUN, 
Assistant in the Museum of the Boston Society of Natural History. 
Read March 9, 1875. 
We have given in this paper descriptions of the trilobites 
and of all the species of mollusks, not including the brachio- 
pods, collected by the parties of the Morgan Expeditions, in 
1870 and ’71, from the Devonian rocks of the plain around 
the little village of Ereré. In the Bulletin of the Buffalo 
Society of Natural Science, for January, 1874, Vol. I, No. 
4, Prof. Hartt has described at length the geography and 
geology of the Ereré-Monte-Alegre district, in which occur 
the fossiliferous Devonian beds forming the plain of Ereré. 
These beds consist of thin horizontal layers of white and 
reddish sandstones, interstratified more or less with shales. 
Both the sandstones and the shales contain at a few points an 
abundance of fossils, closely related to, and in some cases 
identical with, forms characteristic of the middle Devonian 
rocks of North America. The brachiopods, the most abund- 
ant fossils in the Ereré Devonian, were described by Mr. 
Rathbun in the work above cited, in a paper immediately 
following that of Prof. Hartt. There then remained for des- 
cription the mollusks, including six forms of gasteropods 
and eight of lamellibranchs, with a single form of Tentacu- 
lites, two forms of trilobites of the genera Dalmania and 
Homalonotus, both probably new, and a number of obscure 
forms, many of which are entirely unrecognizable. 
The mollusks and trilobites in the Devonian at Ereré are 
confined entirely to. the sandstone, no traces of either having 
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