388 Professor E. Forbes Notes. 



Notes of Professor Edward Forbes' Excursion to the Hebrides. 

 Communicated by the Author. 



We visited Loch Staffin in Skye, to examine the fresh, or 

 brackish water strata, discovered by Sir Roderick Murchison, 

 and supposed to be equivalents of the English Wealdens. 

 Favourable circumstances enabled me to determine their 

 exact position. They rest upon the great sheet of columnar 

 basaltic trap, which covers the oolitic sandstones, lime- 

 stones, and shales (the uppermost portion of which beds have 

 been referred to the cornbrash), of the coast of Skye, from 

 Portree to Loch Staffin. They are covered by beds of shale 

 and clay abounding in Belemnites and Ammonites, all cha- 

 racteristic Oxford clay species, and in beautiful preservation. 

 The Oxford clay underlies the great mass of amygdaboidal 

 and other traps, which form the picturesque line of hills from 

 the Stove to the Guiraing, above Loch Staffin. The brackish - 

 water beds of the latter locality are consequently exactly 

 equivalent to similar beds observed by Mr Robertson at 

 Brora. 



The dredge did not bring up any new testaceous mollusca 

 during our cruise. Near Croulin Island, however, when 

 dredging on the pleistocene clay or mud bed at a great depth, 

 among other fossils we procured a broken shell of the Nucula 

 thraciceformis of Gould, hitherto known only as a recent 

 North American species. In the same neighbourhood we 

 dredged a magnificent addition to our marine molluscous 

 fauna, in the shape of a gigantic compound Ascidian of the 

 Clavelina group. 



In the Minch and at Croulin, we dredged a very fine Ho- 

 lothurian of the genus Fistularia^ quite distinct from any 

 known British species. Also a second species of Sarcodictyon. 



With the tow-net we were very fortunate. In the sound 

 of Mull we procured a new species of Slabberia, a new genus 

 allied to Sarsia, three new species of Sippocrene, two species 

 of Diphyes (D. truncata, and D. hiloba of Sars), and two forms 

 of Physograde medusae. 



In the Minch we met with several examples of a beautiful 



