1850.] HARKNESS NEW RED SANDSTONE, DUMFRIESSHIRE. 389 



raer ; at this locality the clay contains Nucula ohlonga, Brown, which 

 appears to have lived and died on the spot ; as in all the specimens 

 the two valves were united, and appear not to have suifered the least 

 abrasion. 



"I send you these facts, as they maybe of service to you in specu- 

 lating upon the origin of these beds." 

 20th April, 1850. 



3. On the New Red Sandstone of the Southern Portion of 

 the Vale of the Nith. By Robert Harkness, Esq. [Com- 

 municated by the President!] 



[Abstract.'] 



The sandstone occurring in the southern portion of the Vale of the 

 Nith forms the north-west extremity of the great triassic formation 

 which, commencing south of Appleby in Westmoreland, passes north- 

 ward, having the mountain limestone for its eastern boundary, until 

 it reaches Dumfriesshire. Its western boundary is also mountain 

 limestone until it comes in contact with the eastern extremity of the 

 West Cumberland coal-field, from whence it turns westward, skirting 

 the edge of this formation, until it reaches the sea near to the en- 

 trance of the Solway Firth, under which it passes and again reappears 

 in the southern portion of Dumfriesshire. 



The eastern limit of the new red sandstone in Dumfriesshire is the 

 parish of Canobie, where it is seen in the bed of the river Esk at 

 Canobie Bridge. Its northern extremity in this parish is met with 

 a little higher up the river at a place called Knottyholm, near to which 

 the Canobie coal-field commences. The new red sandstone forms 

 the southern portion of this parish ; from whence it ranges westward, 

 and passing through the greater portion of the parish of Half Morton, 

 is again seen and worked extensively in the adjoining parish of 

 Kirkpatrick Fleming. The upper portion of this parish consists of 

 mountain limestone, which forms the northern boundary of the 

 sandstone, and this limestone extends for a considerable distance in 

 a southwesterly direction, forming the northern extremity of the sand- 

 stone in the parishes of Annan and Cummertrees. The sandstone 

 occupies the whole of the former parish except a small portion of its 

 northern part, and in the latter it is confined to the southern end. 

 Besides the parishes already mentioned, of which it constitutes a 

 part, it occupies exclusively the parishes of Gretna and Dornock 

 which lie upon the margin of the Solway Firth. The parish of 

 Ruthwell, west of Cummertrees, and bordering the Firth, is com- 

 posed principally of mountain limestone, and it is probable that near 

 here the sandstone again passes under the waters of the Solway be- 

 fore it reappears in Caerlaverock, west of Ruthwell ; and here com- 

 mences that portion of the new red sandstone to which this account 

 more immediately refers. 



In Caerlaverock the eastern limit of this sandstone cannot be as- 



