Lowell. — Geological Facts. 841 



At Groton, sixteen or seventeen miles west from Lowell, are ex- 

 tensive beds of soapstone, (steatite,) and one lar^^e fjuany is opened 

 and wrought. Among various uses, it is applied to the fabrication 

 of pumps for water. They are neat in their appearance and are 

 stated to be very effectual in drawing water from wells or cisterns, 

 and conveying it into chambers or otlier apartments in which the 

 pumps are placed ; the pistons are made of wood. The soap stone 

 quaiTy at Groton presents some interesting geological appearances. 

 It forms vast beds in mica slaie, and presents decisive indications 

 of having been forced in among the strata by violence. 



While the beds of soapstone are unstratified, they have apparently 

 throvATi the strata of mica slate into positions highly inclined, and 

 even occasionallx vertical ; these strata have been evidently, much 

 disturbed, bent and lacerated, and if we concede this* power to 

 trap, porphyry and granite, it would be difficult to assign a sat- 

 isfactory reason wiiy soapstone should form an exception. We are 

 aware that along with serpentine it is admitted l)y Mr. Brongniart 

 among the igneous rocks, and we can discern no other solution of 

 the appearances at Groton than that of internal igneous action, 

 throwing up the steatite among the strata of mica slate, and thus el- 

 evating them, and at the same time impressing upon them indubita- 

 ble marks of violence. A few miles west of Tjowell, there are beds 

 of white crystalline limestone ; they lie among strata of gneiss, and 

 although the limestone is quarried with considerable difficulty, it is 

 profitably burned for lime. In this quarry are fine fibrous asbestus 

 or tremolite and various other minerals usually found in primary 

 limestone. Granite is WTOught in immense quantities in all the re- 

 gion around Lowell, and especially north of this town. The greater 

 part of it is in boulders, which are split for the purposes of architec- 

 ture. There are however some quarries of granite, and more of 

 gneiss and mica slate, wJiere these rocks are found in place. In 

 Lowell itself, and its immediate environs mica slate is the prevailing 

 rock. It is accompanied however, by many other varieties of slaty 

 rocks, passing froni common slate through siliceous or flinty slate, 

 hornblende slate, he. In some of these dark slates, are delicate veins 

 and knobs, and spots of white calcareous spar. Most of the stratified 

 rocks are highly inclined, some of them almost or quite perpendicular 

 and numerous sections having been made for canals, roads, buildings, 

 &c., and the Merrimack itself flowing through a vast natural canal 

 discloses the strata standing nearly on edge, and rounded and worn 

 by the waters. 



