272 Dr. F ITT ON on the Geology of the 



served at the following places In the counties of Dublin and Wick- 

 low. On the western side of the granite, in a streamlet joining the 

 Dodder^ west of the glen above Ballinascorney ; at Gclden-hiiL^ near 

 the granite quarries ; and at K'dranelagh : on the eastern side, at 

 Killiney^ at the southern extremity of the Scalp ; at Jonelagee, near 

 Jighavanagh to the eastward ; and at the south-western side of 

 Croghan Kinshela. On the shore of Dublin bay, between Booters- 

 toivn and Blackrock, a mass of compact limestone is visible wdthin 

 a few fathoms of the granite, but in the interval the rock is con- 

 cealed. 



Near Ballinascorney^ on the western verge of the granitic moun- 

 tains nearest to Dublin, rocks of the trap family occur ; and from 

 thence to the south-westward, along the borders of the counties of 

 Wicklow and Kildare, various intermediate rocks between the 

 granitic tract above mentioned, and the limestone of the flat country 

 to the westward will be found. At ArUoiv-roch^ on the south- 

 eastern extremity of the county of Wicklow, columnar rocks of the 

 trap family liave been observed by Dr. WcUaston and the Rev. Dr. 

 Brinkley. 



The quarries in the more immediate neighbourhood of the city, 

 afford many varieties of calcareous productions. The Calp of Mr. 

 Kirwan, a variety of limestone, of which an excellent description and 

 analysis have been published by Mr. Knox,* is the prevailing rock. 

 Brown-spar (Jameson) is found in veins at the quarries near Dol- 

 phinsharn ; and beds of magnesian limestone w^ere observed by Mr. 

 Stephens in the bed of the river Dodder, at Miltown^ and at Classons- 

 bridge^ above that place. The petrifactions, which abound in many 

 -parts of this limestone country, the Calp^ and the beds of magnesian 



* Transactions of the Roy. Irish Acad. vol. viii. p. 207. 



