402 Sir Roderick L MurchisorCs 



the researches of Mr. Salter some worm tracks and the trace of 

 an obscure crustacean. 



" The Highland rocks of this age, as well as their equivalents, 

 the Huronian rocks of North America, have as yet afforded no 

 trace whatever of former life. And yet, such Cambrian rocks are 

 in parts of the Longmynd, and especially in the lofty mountains 

 of the North-western Highlands, much less metamorphosed than 

 many of the crystalline rocks which lie upon them. Rising in 

 the scale of successive deposits, we find a corresponding rise in the 

 signs of former life on reaching that stage in the earlier slaty and 

 schistose rocks in which animal remains begin clearly to show 

 themselves. Thus, the Primordial Zone of M. Barrande is, ac- 

 cording to that eminent man, the oldest fauna of his Silurian 

 basin in Bohemia.* 



" In the classification adopted by Sir Henry de la Beche and 

 his associates, the Lingula flags, (the equivalent of the ' zone 

 primordiale ' of Barrande), are similarly placed at the base of the 

 Silurian system. This primordial zone is also classed as the low- 

 est ^ilurian by De Verneuil, in Spain ; by James Hall, Dale 

 Owen, and others, in the United States, and by Sir. Wm. Logan, 

 Sterry Hunt, and BiUings, in Canada.f 



" In the last year M. Barrande has most ably compared the 



* I learn, however, that in Bohemia, Dr. Fritzsch has recently dis- 

 covered in strata lying beneath the mass of the primordial zone of Bar- 

 rande, and in rocks hitherto considered azoic, the fossil burrows of 

 annelide animals similar to those of our own Longmynd. 



f In completing at his own cost a geological survey of Spain, in 



which he has been occupied for several years, and in the carrying out 



of which he has determined the width of the sedimentary rocks of the 



Peninsula (including the Primordial Silurian Zone, discovered by that 



zealous explorer, M. Casiano de Prado,) M. De Verneuil has in the last 



few months chiefly examined the eastern part of the kingdom, where 



few of the older palaeozoic rocks exist. I am, however, informed by 



him that Upper Silurian rocks with Cardiola interrupta, identicaj with 



those of France and Bohemia, occur along the southern flanks of the 



Pyrenees, and also re-occur in the Sierra Morena, in strata that overlie 



the great mass of Lower Silurian rocks as formerly described by M. 



Casiano de Prado and himself. The southern face of the Pyrenees, he 



further informs me, is specially marked by the display of mural masses 



of Carboniferous strata, which, succeeding the Devonian rocks, are not 



arranged in basin-shape, but stand out in vertical or highly inclined 



positions, and are followed by extensive conglomerates and marls of 



Triassic age, and these by deposits charged with fossils of the Lias. 



