Morgan Expeditions. Ill 



been found in the shale, in which the only recognizable forms 

 are the very abundant Discina and two species of Lingula, 

 already described. 



By reference to the paper on the Brachiopoda of Erere, 

 mentioned above, it will be seen that many of the forms 

 there described are identical with species of the Devonian 

 age, more especially the Hamilton group, of New York 

 state, and that most of the remaining forms have closely 

 related ones in these same deposits of North America. The 

 close relation in horizon of the middle Devonian of New 

 York and the formations of the plain of Erere was thus 

 demonstrated. The study of the mollusks has greatly 

 strengthened the proof of this relationship, for several of 

 the forms of mollusks from Erere have proved identical with 

 forms recently described from the Hamilton group of New 

 York by Prof. Hall, and possibly others, now apparently 

 distinct, may also turn out identical with more extended col- 

 lections. All the genera represented, with a single excep- 

 tion, are common to the Devonian elsewhere. We are under 

 very many obligations to Prof. James Hall of Albany, N. Y., 

 for identifying for us many of the following genera, some 

 of which have been recently proposed by him. He also 

 made a comparison of the species with the New York forms 

 contained in his collection, and it was with his aid that we 

 were enabled to unite the three forms, as hereinafter indi- 

 cated. To Mr. R. P. Whitfield, of Albany, we are also 

 much indebted for assistance in our work. 



TRILOBITES. 



Genus DALMANIA, Emmrich. 

 Dalmania Paituna, sp. nov. 



Animal of medium size, sometimes quite large : test very tumid, and 

 with the different lobes and segments sharply defined. 



Buckler crescent-shaped ; greatest breadth about one and one-fourth 

 the greatest length, and nearly twice the length of the glabella ; in front 

 sub-acuminate or bluntly sub-angular, the margins on either side diverg- 



