CORNISH POST-TERTIARY GEOLOGY. 



27 



STREAM-TIN SECTIONS. 



The records of stream-tin sections are so numerous and interesting 

 that it is difficult to make a selection without giving the stock 

 instances of Par and Pentuan and Carnon ; these, as well as some 

 interesting sections given by Mr. Henwood, in which probably con- 

 temporaneous beds are marked, have been omitted through want of 

 space, and a host of lesser sections are represented by samples here 

 and there. 



(Fig. 20). By Mr. S. R. Pattison.' Fowey Valley Works : 



Fig. 20. FowEV Valley Works. 



14ft. Oin. 

 2ft. to 3ft. 



4ft. to 5ft. 

 1ft. to 7ft. 

 3ft. Oin. 



a. Peat 



b. Fine washed sand 



c. Peat, containing wood, ferns, hazel nuts, etc., well preserved, 

 also the horns of deer 



d. Sand and rounded stones, with much tin 



e. Peat, very hard and black, containing numerous trees, etc. ... 



f. Peat, with a large tree trunk, found in June, 1847. 



G. Granite shelf, on which large quantities of tin were found. 



F. Possible fault, downthrow 5 feet, lined with small quartz 

 crystals. [Mr. Pattison has since informed me that he is in- 

 clined to refer this faulted appearance to unequal erosion of the 

 shelf at a quartz vein.] 



Par and Pentuan. 



In a shaft in the lower ground, near Par Estuary, a bed of sea 



sand 4 feet thick, containing shells, was met with at 16 feet 6 inches 



from the surface, between two beds containing traces of vegetation 



mixed with debris. The description^ of this section is not suffi- 



• Trans. Roy. Geol. Soc Corn. vol. vii. p. 34. 



^ Report on the Geology of Cornwall and Devon, p. 403. 



