l78 THE CANADIAN NATURALIST. [Vol. \U.. 



-ever, is not pretended to resemble that of Prototaxites except in-, 

 the vngiie statement of a pseudo-exogenous growth. Lessonia I 

 have not examined, but the horny Laminarice of our North 

 American seas have no resemblance in structure to Prototasites,. 

 Nothing further, I think, need be said in reply to Mr. Car- 

 ruthers' objections ; and Nematojjhi/cus may be allowed to take 

 its place along with a multitude of obsolete fucoids which strew 

 the path of palasontology. As to Prototaxites, it is confessedly 

 an obscure and mysterious form, whose affinities are to be dis- 

 cussed with caution, and with a due consideration of its venerable 

 age and state of preservation, and probably great divergence from 

 any of our modern plants; and it is to be hoped that ere long 

 other parts than its trunk may be discovered to throw light on 

 its nature. Until that takes place, the above remarks will be 

 sufficient to define my position in regard to it; and I shall decline 

 any further controversy on the subject until the progress of dis- 

 covery reveals the foliage or the fruit of this ancient tree, belong- 

 ing to a type which I believe passed away before even the Car- 

 boniferous flora came into existence. 



GEOLOGY AND MINERALOGY. 



Bone Cave in Kirkcudbrightshire. — It lias long been 

 familiar to geologists that the western and southern coast-line of 

 Scotland is pierced with caves of different levels, indicating for- 

 mer successive lines along which the sea-waves worked. Unfor- 

 tunately, owing to the want of limestone, or very calcareous 

 rocks, these caves, as a rule, present none of that stalagmite- 

 deposit which has elsewhere served so abundantly to cover over 

 and preserve the remains of the ancient denizens of our country^ 

 with traces of the presence of man himself. The caves usually 

 open directly upon the coast, with free exposure to the air, so 

 that the floors show nothing but damp boulders and pools of 

 water from the drip of the roof. Recently, however, a renaark- 

 able exception to these ordinary conditions has been observed on 

 the wild cliff-line to the south-west of the bay of Kirkcudbright- 

 The Silurian greywacke is there traversed with striags and veins 

 of calcite along lines of joint and fracture, and at one point where 

 an old sea cave occurs, the walls and floor at the cave mouth, and 



