Geology of Ber^soicJcshire, 641 



from the uninjured state of the walls which now stand, we 

 have every reason to think that the building might have 

 remained to this day, a lasting memorial of times long gone 

 by, if the barbarous conduct of an English warrior had not 

 consigned it to destruction. It was destroyed, along with 

 many other convents in Merse and Teviotdale, by the Earl of 

 Hertford, in 1545. 



The interesting monument at Crosshall, distant about a mile 

 from Eccles, which consists of an entire column of sandstone 

 covered with sculptures, above 1 5 ft. high, and appears to be 

 scarcely less ancient than the convent, has been also derived, 

 in all probability, from the quarry of Eccles. 



In the north of the parish of Eccles, this sandstone contains 

 an unusual quantity of silica, and is so hard as to be almost 

 a quartz rock. The whole of the parishes of Eccles and 

 Swinton, and the southern parts of Greenlaw and Polwarth, 

 belong to this formation. 



The marly sandstone, from its dark colour and slaty struc- 

 ture, is liable to be mistaken, and has been considered by some 

 as belonging to the coal measures. The characters* which 

 distinguish it as a member of the new red sandstone formation 

 are sufficiently strong and irresistible, and show that its de- 

 position must have been subsequent to that of the coal series : 

 for, first, it contains beds of sulphate of lime, a mineral which 

 characterises this formation ; and, secondly, it lies over the 

 magnesian limestone, a rock which we are immediately to 

 consider, and which is exposed in two different parts of the 

 parish of Eccles. 



On the east side of Birgham Haugh, the north bank of the 

 Tweed, which hitherto we have described as consisting of 

 sandstone, is composed of amygdaloid. This rock assumes 

 two aspects: that portion of it which constitutes the round 

 irregular masses and rocky islets in the middle of the river, 

 and which are the means of forming several fine angling 

 streams, has a wacke basis approaching to clay. Through it 

 are interspersed crystals of calcareous spar, and its cavities 

 contain green steatite and stilbite. The rock which more 

 properly constitutes the bank of the river is nearly allied to 

 greenstone ; but the almond-shaped cavities are still present, 

 and they contain small round masses of quartz. This mineral 

 continues exposed for 100 yards, when the sandstone again 

 appears. 



Magnesian Lirnestone. — This rock makes its appearance at 



the west side of Birgham Haugh, and constitutes the bed cf 



the river. Its exteinal aspect is lighter-coloured and more 



compact than the English dolomite; it is very difficult to frac- 



VoL. V.-— No. 29. TT 



