90 The Testimony of the Rocks. 



sure during silicification," As, however, they also occur in the best 

 preserved fragment of the plant which I have yet seen, — a Thurso 

 specimen which I owe to my friend Mr. Dick, — I deem it best to 

 regard them, provisionally at least, as one of the characteristics of 

 the plant. I may mention, that while I disinterred one of my 

 specimens from the Thurso flagstones, where it occuired among 

 remains of Dipterus and Asterolepis, I derived another specimen 

 from the great overl^^ing formation of pale Red Sandstone to 

 which the lofty hills' of Hoy and the tall mural precipices of Dun- 

 net Head belong ; and that this plant is the only organism which 

 has yet been found in this uppermost member of the Lower Old 

 Bed, to at least the north of the Moray Frith. Another appa- 

 rently terrestrial organism of the lower formation, of, however, 

 rare occurrence, very much resembles a sheathing bract or spathe. 

 It is of considerable size, — from four to six inches in length, by 

 from two to three inches in breadth, — of a broadly elliptical and 

 yet somewhat lanceolate form, deeply but irregulai'ly corrugated? 

 the rugae exhibiting a tendency to converge towards both its 

 lower and upper terminations, and with, in some instances, what 

 seems to be the fragment of a second spathe springing from its 

 base. Another and much smaller vegetable organism of the same 

 beds presents the form of a spathe-enveloped bud or unblown 

 flower wrapped up in its calyx ; but all the specimens which I 

 have yet seen are too obscure to admit of certain determination. 

 I may here mention, that curious markings, which have been 

 regarded as impressions made by vegetables that had themselves 

 disappeared, have been detected during the last twelvemonth 

 in a quarry of the Lower Old Red Sandstone near Huntly, by 

 the Rev. Mr. Mackay of Rhyuie. They are very curious and 

 very puzzling ; but though some of the specimens present the 

 ap23earance of a continuous midrib, that throws oft", with a cer- 

 tain degree of regularity, apparent leaflets, I am inclined to regard 

 them rather as lying within the province of the ichnologist than 

 of the fossil botanist. They bear the same sort of resemblance 

 to a long, thickly-leaved frond, like that of the "hard fern," that 

 the cast of a many-legged annelid does to a club moss; and I 

 was struck, on my first walk along the Portobello beach, after 

 examining a specimen kindly sent me by Mr. Mackay, to see how 

 nearly the tract of a small shore crab [Carcinus Moenas) along 

 the wet sand resembled them, in exhibiting what seemed to be an 

 obscure midrib frino-ed with leaflets. 



