Charles Dawson — Ancient and Moclern '^ Dene Holes" 293 



JEstheria Hindei, J., from Plioenixville, Pennsylvania (Geol. Mag., 

 Dec. Ill, Yol. VIII, 1891, p. 51, PI. ^X, Figs. 5-8), measures 

 7 by 4-5 mm., and is nearly oblong, that is, higher anteriorly ; and 

 although much like the Kansas jEstheria, its relative size, small 

 umbo, and boldness of the concentric stri^ are distinctions ; and 

 there is no trace of its bar ornament in the other form. 



Imbedded in a coarse sandstone, the Kansas EsthericB are too badly 

 preserved to exhibit their interstitial sculpture. Their concentric 

 lines of growth are recognizable (Fig. 3), but nothing else 

 satisfactorily. There is a delicate, siliceous, irregularly reticulate, 

 white infiltration among the grains of quartz (Fig. 4), which gives in 

 the hollow casts a false appearance of ornament, especially where 

 the concentric lines are pi-esent ; but it cannot be so regarded at all. 



The relative specific value of the North-American Estlierice and 

 portions of their ornament, figured in the " Monogr. Foss. Estherife," 

 1862, has been estimated by me in the Geol. Mag., 1890, p. 386, 

 and 1891, p. 51. 



The conclusion arrived at is, that the Eaiherim from the Eed Beds 

 (or Cimorron Series) of Kansas and Oklahoma should be registered 

 the same as the Triassic JEstheria miniita (Alberti). If, however, the 

 interstitial ornament is found well preserved, it may prove the 

 sjoecies to be different. 



III. — Ancient and Modern "Dene Holes" and their Makers. 

 By Charles Dawson, F.S.A., F.G.S. 

 (PLATES XI AND XII.) 

 rpHE name " Dene Holes " has been locally given to certain 

 JL ancient artificial caverns usually found excavated in the Chalk 

 of Essex and Kent. They have deep vertical entrances by shafts, 

 being of varying depth, but the caverns themselves all bear 

 a general similitude in design. They have been chiefly explored 

 in the counties of Essex and Kent, although they undoubtedly 

 exist in many other counties.^ 



In places where the chalk stratum is overlain by some other 

 deposit, the latter has been cut through by a shaft and the chambers 

 have been formed in the solid chalk below, leaving as a rule only 

 sufficient chalk between the cavity and the superincumbent strata to 

 ensure the stability of the roof. 



No spoil heaps of chalk are found near them on the surface, 

 showing that the chalk taken out has been disposed of, and un- 

 fortunately nothing has been discovered within the chambers which 

 gives any decisive clue to their age, origin, or use, although from 

 objects discovered many are thus proved to have been in existence 

 for some centuries. 



It has been surmised by some that they have been used as 

 habitations, but there is not the slightest internal evidence of this. 



1 The -writer and Mr. John Lewis, C.E., F.S.A., descended two very fine ones at 

 Brighton, Sussex. One of these was incomplete with respect to depth. In the floor 

 were excavated two or three steps. The workmen seemed to have been excavating 

 the chalk laterally from these steps and thus lowering the floor. 



