SKY. GEOLOGY. SECONDARY STRATA. 329 



by trap veins. Neither the thickness, the number, nor 

 the order of these beds can be ascertained, as they are 

 much too complicated and difficult of access to admit 

 of such an examination. The very attempt would be 

 a superfluous endeavour after accuracy, since enough of 

 them is ascertained to prove that which alone is important 

 to be known, namely, the order of their arrangement, and 

 the characters by which they are identified with the other 

 strata already described. In general they are disposed 

 alternately in thin and thick laminae, formed of a dark blue 

 earthy limestone, at times somewhat crystalline, and inter- 

 leaved with argillaceous schist of various dimensions. These 



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beds are here inclined at an angle of about twenty-five de- 

 grees; they seem most regular as well as thickest at the 

 point of separation between the two Lochs Eynort and 

 Slapin ; while near the same place they are also occasionally 

 found in very thin schistose lamina, so that no rule can be 

 laid down respecting them : I may add that they are found 

 occupying the island of Heast, as well as a long ridge of 

 rocks which here intersects Loch Eishort. 



It is now proper to remark, that although the general 

 aspect and disposition of the calcareous beds on this 

 shore is the same as on the Broadford side, and that 

 they contain the same organic remains, they present 

 differences that serve to mark the commencement of the 

 change from the common stratified to the irregular crys- 

 talline rock. While the beds are thicker they are also 

 much harder, and more frequently approach to the crystal- 

 line state ; and in lieu of the tender shale which there 

 separates them, they are here divided by a hard schist 

 having the characters of a fine graywacke. Under similar 

 circumstances it has already been seen, that quartz and 

 indurated sandstone are found occupying the place of 

 the ordinary soft sandstone which occurs among the 

 common limestone. 



The obscurity which hangs over the connexion of the 

 stratified and unstratified limestone in the interior, is here 



