318 PROCEEDINGS OF THE AMERICAN ACADEMY 



This description, which is quite imperfect, was made out from a speci- 

 men of unknown locality^ procured, some twenty-five years ago, by Dr. 

 Harlan, from the collection of our well-known mineralogist, Mr. Francis 

 Alger. That it is the same with the more conspicuous of our Quincy 

 fossils is, I think, established by the comparison of a nearly complete 

 specimen of the latter with the cast of P. Harlani taken from Mr. 

 Alger's specimen, the original never having been returned. Consid- 

 ering the perfect agreement in lithological characters of the matrix as 

 described by Green with that of the Quincy fossils, and the immediate 

 recognition of this identity of mineral features by Mr. Alger on seeing 

 my Quincy specimens, we can hardly doubt that the original speci- 

 men of P. Harlani came, either directly or through the drift scattered 

 in the vicinity, from the same fossiliferous belt. Thus it appears that 

 this vagrant fossil, so long without a local habitation, although not with- 

 out a name, has at length been restored to its native seat, where it 

 takes a prominent place in the dynasty of ancient living forms that 

 marked the earliest paleozoic history of New England. 



" In this connection I find a remark in Barrande which, besides 

 being historically curious, has an interesting bearing on the specific 

 affinities of our fossil : ' We see in different collections, and especially 

 in that of the School of Mines and the British Museum, under the 

 name of P. Harlani, from the United States, a cast of a trilobite 

 which appears to us to be identical with P. spinosus, of great size, 

 such as found at Skrey in Bohemia.' The cast here referred to, 

 like that used in my comparison with the Quincy fossil, was doubtless 

 one of the series of plaster copies prepared by Dr. Green to accom- 

 pany his monograph. Its agreement with the P. spinosus harmonizes 

 well with my own observation, already stated, of the close resem- 

 blance between the Quincy fossil and this Bohemian species. 



" The occurrence of well-preserved fossils among rocks so highly 

 altered, and so contiguous to great igneous masses, as are the fossilifer- 

 ous slates of Quincy, may well, encourage us to make careful search 

 in other parts of New England where heretofore such an exploration 

 would have been deemed useless. Although we cannot hope to build 

 up the geological column of New England from the protozoic base 

 just established to the carboniferous rocks, supposing all the interven- 

 ing formations to be represented in this region, we may at least suc- 

 ceed in determining, by fossils hereafter discovered, some of the 

 principal stages in its structure, and in thus relating its strata definitely 

 to the great paleozoic divisions of our Appalachian geology." 



