Crosby.] 480 [April 7, 
Dr. Wadsworth’s paper was discussed by Prof. R. H. 
Richards, Mr. W. O. Crosby, and President Bouvé. 
General Meeting. April 7, 1880. 
Vice-President, Mr. 8. H. Scudder,.called the meeting to 
order. Twenty-seven persons present. . 
Mr. Scudder read a paper on the Devonian Insects of 
New Brunswick and their relation to the Doctrine of De- 
scent. 
The following paper was also read : — 
On THE AGE AND SUCCESSION OF THE CRYSTALLINE FORMA- | 
TIONS OF GUIANA AND Braziut. By W. O. Crossy. 
INTRODUCTION. 
The last quarter of a century has witnessed great progress in our 
knowledge of the stratified crystalline or eozoic formations; and no- 
where is this advance more evident than in eastern North America. 
The stratified crystalline rocks of this part of the globe are no longer 
generally regarded merely as metamorphosed equivalents of the vari- 
ous Paleozoic terranes, but the portion so disposed of at the present 
time is comparatively small and yearly diminishing; and, with the 
exception of some limestones, nearly all crystalline sediments are 
now set down by a large number of the best geologists as unquestion- 
ably Eozoic. Nor, on the other hand, are these confessedly ancient - 
sediments now habitually classed under the single designation of 
“ primitive” or “crystalline,” viewed as possibly largely of igneous 
origin, and referred to one grand epoch of past time. On the con- 
trary, while their aqueous or sedimentary origin stands almost unques- 
tioned, it is generally conceded that they are susceptible of chrono- 
logical division equally with more recent formations; these divisions, 
in the almost complete absence of paleontological data, being based 
1 Published in the Anniversary Memoirs of the Society. 
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