CHEMICAL SCIENCE. 259 



into a warm ocean containing lime salts, easily decomposed by the soda salts, 

 we nave chemical action on an extended scale. The result of this action 

 must be some form or forms of carbonate of lime, fitted either for the habita- 

 tions of shell-building fish, or for consolidating calcareous rocks. \ 



Returning to the first exhibition of chemical change, we see the influence 

 of the minute quantity of organic matter dissolved in the water a constituent 

 so smafl in weight that it has been generally neglected in the analysis of 

 waters and yet, under favorable circumstances, becoming a sufficient cause 

 in bounding a coast line with cliffs, or even producing a rock formation. 



As the facts cited might be considered an unusual occurrence, favored by 

 certain local causes, Dr. Hayes in a subsequent paper referred to another in- 

 stance where, from similar changes, the water flowing below the surface, and 

 constituting the drainage of the country, is largely composed of a solution of 

 the bicarbonate of soda. 



The subterranean waters of the peninsular of Boston, have at the depth of 

 about 140 feet, a remarkable uniformity of composition, and the flow toward 

 the shore h'ne is abundant. Like the water of the lower Mississippi, they are 

 turbid, holding in suspension finely divided carbonate of lime and iron, and 

 hydrate of silicic acid ; affording, when greatly heated, a precipitation of hy- 

 drated carbonate of lime, due to the instantaneous decomposition of sulphate 

 of lime, by a solution of bicarbonate of soda present. The latter salt is in 

 these cases always in excess ; so that the whole mass of the drainage, at 

 about the same level, has a marked alkalinity, and belongs to the class of 

 alkaline waters. 



Numerous observations have shown that this water is covered by a com- 

 pact marl-earth, which has so large a proportion of clay that it effectually di- 

 vides the upper drainage from the lower, or alkaline water, which, from its 

 depth below the surface, can enter the harbor water only at some distance 

 from the shore. When attempts have been made by continuous pumping for 

 many days, to exhaust the supply; or overcome the flow of the water at one 

 point, the wells or borings at contiguous points have shown a reduction of 

 volume in the water ; but a reflux of the ocean water through the same chan- 

 nels has been effected only where, after several days, a very large volume of 

 water had been pumped from one opening. This fact establishes our knowl- 

 edge of a continuous flow of alkaline water toward the sea from the shore 

 line, while the depth of the stratum under which it flows, shows that it is 

 overlaid by the mass of sea-water near the shore. A continuation of solid 

 marl stratum below the water near the shore, would prevent any intermixture 

 of the alkaline water with the sea-water at that point, and allow it to gradu- 

 ally mix only when the soundings are about twenty-five fathoms. There is 

 no cause apparent, which would prevent a continued suspension of the mi- 

 nutely divided matter, until the turbid water mixes with the sea- water. In 

 the cases of pumping referred to, the water, after some days, became more 

 turbid than at the commencement of the trials, leading to the conclusion that 

 turbid water occupied every part of the submarine channels of flow. 



Proceeding to the more distant sources of this water, I have resorted to 

 chemical analyses of the waters from various points hi the vicinity of Boston, 



