20 Mr. N. J. Winch on the Geology of 



Impressions of the bark of a plant resembling a cactus or euphor- 

 bia, (Sowerby, tab. 49.) from MurtonMain colliery; and (Parkinson, 

 vol. i. tab. 1. fig. 6.) from Benwell colliery. In coal. 



Vegetable impressions (vide Parkinson, vol. i. tab. 3. fig. 1.) from 

 Gateshead Fell. In sandstone. 



Cast of a cane-like vegetable, (Parkinson, vol. i. tab. 3. fig. 3.) 

 from near Coley hill dyke; and (Parkinson, vol. i. tab. 5. fig. 8.) 

 from Muston colliery. 



An aggregate of black quartz crystals diverging from centres ; 

 having the interstices filled with yellow ochre. It is a mineralized 

 tree, and it found at Bigge's main colliery, and often in large masses 

 on the sea beach. 



Bivalve shells * resembling those of the freshwater muscle, in 

 dark-grey ironstone, from Wylam and Muston collieries. 



Bivalve shells resembling the preceding but much less in size, in 

 a stratum of black shale and ironstone ; from the rocks in the Tyne 

 at Low Lights, and from Heaton Dean, near Busy cottage. 



Bivalve shells like the last, about half the size of freshwater muscle 

 shells, in black shale, from Hebburn colliery, at the depth of 130 

 fathoms. These shells are generally less common in the shale than 

 in the ironstone that accompanies it. 



I have only to remark on the preceding catalogue that it contains 

 no marine genera ; and I do not believe that any marine shells, 

 zoophytes, or corallines have ever been detected in the coal mea- 

 sures of this district. 



* Very similar shells are found in the Clackmannanshire coal-field at North Alloa, in 

 that of Staffordshire at Tividale, and in the great coal-field of Derbyshire and Yorkshire, 

 where the bed of ironstone that contains them is called the Muscle band. [Communicated 

 by Mr. Warburton.] 



