298 LINES OF ELEVATION PROCEEDING FROM THE BREIDDENS. 



When measured with precision, these lines of elevation, instead of being strictly pa- 

 rallel, are found to diverge gradually from each other as they proceed to the E.N.E., 

 while to the W.S.W. they converge towards the Breiddens, and finally are coincident 

 with the fissure on which those hills were erupted. They therefore resemble the great 

 longitudinal, fan-shaped lines of disturbance which range through the coal-field of Coal 

 Brook Dale, proceeding from the hill of Lilleshall as a volcanic nucleus. (See pp. 110, 

 234, Map, and further observations following the description of the Dudley Coal-field 

 and Lickey Hills.) 



The discovery of a large elliptical basin of lias, the major axis of which is parallel to 

 these axes, adds much interest to the case. This basin, as already described, p. 22, is 

 flanked on the S.S.E. by the Hawkstone and Market Drayton Hills, whilst on the N.N.E. 

 it is bounded, though at a greater distance, by another range of New Red Sandstone, 

 which rising near Malpas, extends into the hills of Bickerton, Bulkeley, and Peckforton. 

 This last-mentioned range of hills also slightly diverges from the main axis of the 

 Breiddens, trending from south-west to north-east, and coincides remarkably in mi- 

 neral characters with the ridges just described. Thus, at Bickerton is a mass of hard, 

 white, compact sandstone, coated with black oxide of manganese like that of Pirn Hill, 

 and dipping to the north-west, whilst other beds of red marl and sandstone incline to 

 the south-east; and though the prevailing dip of these hills between Beeston and 

 Bickerton is to the south-east, there is a transverse disruption in the central part (Peck- 

 forton and Bulkeley) where the strata are thrown over to the N.W. and W.N.W. On 

 the south-eastern face of the Peckforton Hills, copper ores have been extracted to a 

 small extent. These ores occur in strings and veins associated with dislocations more 

 or less transverse to the main direction of the red sandstone, the only exception with 

 which I am acquainted being in Stanner Hill, where certain poor mineral veins appear 

 to range from south-west to north-east, or parallel to the ridge. Sulphate of barytes is 

 not unfrequent, and Sir Philip Egerton informs me that it is frequently disseminated 

 through the sandstone. 



From the undisturbed position of the lias between the two fan-shaped lines of ele- 

 vation, which threw up the New Red Sandstone of the Hawkstone Hills on the one 

 side, and the Peckforton on the other, it may be inferred that eruptive forces have 

 destroyed an overlying mass of that formation which may have once extended so far 

 towards the south-east, as to connect this outlier with the main escarpment of the 

 formation, while the intervening region was left in a tranquil state ; and thus the pre- 

 servation of this singular outlier is satisfactorily explained. 



We shall afterwards extend this inquiry and apply the same tests to other districts, 

 particularly to the red sandstone surrounding the great coal-field of Dudley and Wol- 

 verhampton, and extending to the south of the Lickey Hills, with the view of deter- 

 mining the periods at which such tracts have been disturbed ; and we shall again show 

 that great periods of dislocation took place posterior to the lias, on lines of ancient 

 eruption. 



