THE LANSING SKELETON 



147 



engaged with several men in making a cross-tunnel from the westward, 

 intended to strike the original tunnel at about 40 feet from its entrance. 

 Professor Holmes has generously granted the use here of all facts devel- 

 oped by the progress of the cross-tunnel at the date of my last visit. 

 This tunnel was an open cut, so far as excavated at that time, and it 

 afforded a much better chance to inspect the loess by the aid of day- 

 light. The accompanying diagram shows a generalization of the facts, 

 so far as they bear on the skeleton and its relations to glacial histor3^ 

 I gathered samples of the deposit for microscopical examination. 



There are three parts or phases of the deposit penetrated by the tun- 

 nel, each of which ma}^ be briefly characterized, namely : 



1. The layer or stratum, containing rotting limestone slabs, in which 

 the skeleton lay, immediately overlying the ledge of Carboniferous lime- 

 rock. This is quite unctuous when wet and very fine grained. Its out- 



k- Mouth of the Tunnel. 



B - Carboniferous Limestone. 



C - lowan Loess. 



Rotted Pebbfes. 



o o « Rotted Limestone Pebbles. 



Scale: t J^ '?'■'*• 



^ 



" 



~~<. 



TT»"° 











^ 





% * 



^ 









CA 









(« 







• " 



ft> 



Figure \.— Section across the Tunnel, parallel loith the Cross-cut of Mr Foicke. 



ward color is darker than any part of the tunnel; yet it contains lumps 

 of irregular shape that are lighter colored. It may have been derived 

 largely from the shale that overlies the limestone. It is from one to 

 two feet thick. Its reddish brown color and tenacious texture recall the 

 brown clay that is often mentioned below the true loess. Microscopic- 

 ally this substance is found to contain no quartz, but to consist wholly 

 of very fine scaly particles whose nature can not be exactly determined. 

 It does not afford the least effervescence with hydrochloric acid.. The 

 scales appear micaceous or kaolinic, but are usually accompanied by 

 much iron oxide. 



2. The grains of the loess above the stratified clay stratum number 4, 

 three and a half feet above the floor of the tunnel, are quite different, 

 being crystalline, consisting largely of quartz, but containing also plagio- 



