6 HISTORY OF BEITISH ZOOPHYTES. 



zoophytes must have greatly abounded in the primitive seas, 

 and that then, as now, theii' constant employment was to 

 separate the carbonate of lime from the waters, thus forming 

 a habitation for themselves, but at the same time uncon- 

 sciously raising in the deep what was afterwards to be 

 the residence of men, and what was to furnish materials for 

 constructing the cottages of the poor and the palaces of the 

 rich. Most certain it is that the mountain limestone, wliich 

 abounds throughout our land, so useful in agriculture, in 

 architecture, and in the manufacture of iron the most use ful 

 of metals, was prepared at the bottom of the sea to answer 

 all these important purposes. In breaking up the limestone 

 found in our quarries there is abundant proof of its marine 

 origin, for the organic remains, in general so plentifully 

 found in it, are evidently those of molluscous creatures, and 

 of zooph}i;es and other animals known to be denizens of the 

 deep. AYell do I remember the delight I experienced many 

 years ago at finding in a little fertile field in my glebe at 

 Stevenston, to which I had recently given a top-dressing of 

 lime from Hullerhirst, in the same Ayrshire parish, the 

 pretty entire remains of a Cassis, or helmet-shell, similar in 

 some degree to those from foreign lands, wliich are so often 

 placed as ornaments on our mantel-pieces. Though it had 



