1880.] 497 [Crosby. 
strengthened when we examine the southern end of the Orinoco and 
Caratal section, for the rocks south of the Yuruari River are, appar- 
ently, precisely the same as the quartz-porphyry and felstone series 
of Brown and Sawkins. They are usually described as compact, ' 
porphyritic, and banded felsites, distinctly bedded for the most part, 
and interstratified with taleose, hornblendic and other schists. 
It is apparent, then, that the older crystalline rocks of the whole 
vast region of Guiana, so far as it has been explored, may be, and to 
a great extent have been, arranged in three series, which correspond 
closely with the three crystalline series believed to exist in the south- 
ern half of the continent, and which J have stated to possess in a large 
deeree the essential characters of the Laurentian, Huronian, and 
Montalban systems. While unconformably overlying all of these, in 
both sections of the continent, are the itacolumites, semicrystalline 
schists and marbles, which, like the Taconian rocks of North Amer- 
ica, represent a horizon near, but below, the boundary line between 
the Eozoic and Paleozoic. 
General Meeting. April 21, 1880. 
The President, Mr. T. T. Bouvé, in the chair. Thirty-five 
persons present. 
The concluding pages of the preceding paper were read by 
Mr. Crosby. 
Mr. Edward Burgess read a paper on the Anatomy of the 
Milk-weed Butterfly, (Danais Archippus Fabr.)* 
Gen. F. A. Osborn, for the Committee on the nomina-. 
tion of Officers for 1880-81, presented a report. 
Mr. Bouvé said that four years ago he had consented to 
withdraw his resignation as President, but he felt obliged for 
several reasons to decline re-election the present year, and 
begged that the Society would not ask him to reconsider his 
determination. 
1 Published in the Fiftieth Anniversary Memoirs of the Society. 
PROCEEDINGS B. 8. N. H. — VOL. XX. 32 SEPTEMBER, 1881. 
