62 NOTE ON THE CONGLOBATED FOBM OF THE 



a harder and more compact nature, on several parts of the coast, 

 and in the Fulwell Hill Quarries. 



Many years since Prof. Sedgwick gave a careful description 

 of several of these beds, and as I cannot, after long examination, 

 improve his description, I am obliged (inclined rather) to quote 

 some parts of his account of them than attempt something new. 



He says that "this (conglobated) structure is seen in its most 

 imposing form on some parts of the coast of Durham, where the 

 whole cliff resembles a great irregular pile of cannon-balls ; but 

 it is not in those localities that the large spheroidal concretions 

 can be studied with greatest advantage. Their true history will 

 be best understood where they are associated with other modifi- 

 cations of the limestone." 



" Some of these masses (of limestone) have been erroneously 

 called stalactitic. They have not the structure of stalactites, 

 for they are not made up of successive layers arranged about 

 the axes of the pendent cones ; but on the contrary (where the 

 crystalline structure has not been carried too far), we may find 

 them made up of circular plates piled one upon each other, with 

 their planes at right angles to the same imaginary axes, and 

 these plates seem to be the prolongations of the laminse of con- 

 tiguous beds." 



" The last set of concretions to be noticed are to be found in 

 association with the dolomitic earth occupying the cells. They 

 are unattached to any surrounding beds, and are always more or 

 less perfectly spheroidal in form. Sometimes they are single ; 

 but more frequently several spheres are in contact, which by 

 mutually penetrating each other produce a number of grotesque 

 forms; and occasionally they are grouped in beautiful regular 

 clusters. In general they are less crystalline than the globular 

 masses before described, and they do not exhibit the same kind 

 of laminated structure ; but in some instances they are studded 

 with the projecting angles of the inverse rhomb, and on fracture 

 are found, as in the former instances, to be composed of diverg- 

 ing bundles of crystals. The largest of these concretions (which 

 at Fulwell are more than a foot in diameter) have commonly a 

 smooth surface, and when broken in two, expose a number of 



