Rev. R. Henna H on the Limestone of Plymouth. 411 



Stonehouse, and in other parts of the hill near Mill Bay. Some of 

 the specimens of shells and madrepores, which I now send, are 

 from a part of Stonehouse Hill, a little to the west of the quarry 

 at Mill Bay. They were broken from detached stones lying in un- 

 disturbed ground considerably below the surface, and agreeing in 

 appearance with the solid rock. The quarry at Mill Bay lies about 

 a mile and a half east of the Dock Yard. The specimens from this 

 quarry were also broken from detached masses of rock found at 

 different depths. 



Still further to the east, under the citadel, at the east, end of the 

 Hoe, I have found many well-defined shells belonging chiefly to the 

 genus Turbo, some in detached masses, some imbedded in the solid 

 rock ; but the substance of the shell in these specimens is so altered, 

 as to exhibit the colour and texture of the surrounding matter 

 Lastly, in a quarry at Cat-down, I have obtained shells or rather 

 fragments of shells, as well as madrepores, but in small quantity, 

 and not so perfect as elsewhere. It has hitherto been a point in 

 dispute whether the limestone at Plymouth does or does not con- 

 tain organic remains ; but I hope that the specimens which I now 

 send the Society will be considered as deciding the question ; it. 

 must be admitted at the same time, that the instances where shells 

 occur are by no means frequent, and that they are not then found 

 in any quantity. I send herewith a tooth, which, together with 

 many others, and the head and bones of a large animal, was found 

 in the Breakwater quarries at Oreston, at the bottom of a cave or 

 hollow in the limestone rock. It was sent by Mr. Whidbey to Sir 

 Joseph Banks. 



I take this opportunity of observing, that on the eastern side of 

 the Sound, under Statten Heights, and nearly in a line with the 

 great national work the Breakwater, there occurs a remarkable 



