s 



of Boston and its Vicinitij. £17 



lothci- things e<|uaily as probable; but this is nnpbilosophical, 

 and (ends rather to support preconceived opinions, than to lead us 

 to a correct knowledge of the structure of the globe. 



Without bending to any particular theory, we cannot forbear 

 remarking, how many proofs of the accuracy of the observations 

 of Werner are offered by the structure of the rocks in this vicin- 

 ity. These coincidences', at least, encourage the student to pur- 



-^ 



sue his investigations, and invite him cnward with assurances, 

 that Geology is not the science of conjecture. The description 

 given by the pupils of the Wernerian School, of rocks in other 



pplies nearly to similar rock 



fi 



so far as we have ^qX penetrated, that tlie rocks, as Sienite and 

 Greenstone, which Werner calls newer than Argillite, repose on 

 it, and beds of it occur in them, as noticed in other countries, 



'j 



In our map, every bed or iusolated alluvion is not represent- 

 ed ; thus, alluvial hills appear from Needham to the Lower falls 

 in Newtou, pursuing the course of Charles river; yet, the Grey- 



w 



% 



wacke is found among them, and as they do not interrupt that 

 formation, we have thought it not necessary to represent them. 

 Our object has been to present to the student a view of the gen- 

 eral disposition of the rocks, as they appear at the surface ; we 

 have gone as far as facts would guide us, and we have terminated 

 where conjecture began. 



» 



Of ike Alluvion 



(Coloured on the map, gamboge yellow.) 



' The principal alluvion, though irregular, may be considered 

 as bavins: a trianirular form. Its southwest boundary is Grey. 



S3 *" 3 



wacke; its southeast are the waters in the harbour of Boston, and 

 its northwest is Greenstone principally, and Porphyry. It forms 



