51 



tentot crania, the average capacity of which is 75 cubic inches. A 

 cubic inch of brain is estimated to weigh 259.57 grains, and this multi- 

 plied by 75 would give, as the whole weight, about 2 lbs. 1 2 oz. av. 



Mr. Bouve asked Dr. Jackson if he had observed any evi- 

 dence of metamorphic action in the conglomerate rocks of 

 our coast. He had noticed, by the wayside near Hinghain, a 

 blood-red rock, resembling Saugus jasper, which he had sus- 

 pected to be an altered conglomerate, and yet he had never 

 discovered anything of a slaty or pebbly character about it. 

 A short time since, he had found the locality from which 

 these specimens had been taken, near the Ocean House, and 

 had traced it running into true conglomerate. 



Dr. Jackson said that he had often seen this red rock, and 

 had frequently traced it into the slate. In Roxbury, rock peb- 

 bles of quartz and granite were to be found adhering closely 

 together without any sign of cement. Chemistry reveals 

 the fact that the surfaces are composed of silicate of lime 

 formed by the action of heat. In the vicinity of certain trap- 

 dykes in Rhode Island, the pebbles are often covered with 

 crystals of specular and magnetic iron, produced by the 

 decomposition of the sesquichloride under the influence of 

 water and lieat. Argillaceous minerals, also, in conglomerate 

 are often charged with peroxide of iron. He thought this 

 could not be explained by the simple conduction of heat 

 from trap-dykes, but that, in accordance with DAubree's 

 theory, superheated water must have been the active agent 

 in the changes alluded to. 



Messrs. Francis G. Sanborn and J. T. Rothrock were 

 elected Resident Members. 



April 16, 1862. 



The President in the chair. 



Mr. Scudder read the following communication from Mr. 

 E. S. Morse, of Portland, Maine : — 



The HiEMAL and Neural Regions of Brachiopoda. Bt 

 Edward S. Morse. 



In a paper read before the Boston Society of Natural History, by 

 N. S. Shaler, entitled, " Lateral Symmetry in Brachiopoda," it is as- 



