334 THE POPULAR SCIENCE MONTHLY. 



Similar accumulations of fcssil wood occur on the western side of 

 the delta, about the Natron Lakes and in the Bahr-bela-Ma. 



All these trunks have weathered out of a miocene sandstone ; and 

 it has been suggested that, when this sandstone was deposited, the 

 Kile brought down great masses of timber from the upper country, 

 just as the Mississippi sweeps down its " rafts " into the Gulf of Mex- 

 ico at the present day ; and that a portion of these, after long expos- 

 ure and knocking about in the flood, became silted up in the sandy 

 shores of the estuary. 



The greater part of the " petrified forest " is at present one thou- 

 sand feet above the level of the sea, in the midst of the heights which 

 form the eastward continuation of the Mokattam. It has, therefore, 

 shared in the general elevation of the land which took place after the 

 beginning of the miocene epoch. That such elevation occurred is 

 proved by the fact that the marine beds of that period lie upon the 

 upraised limestone plateau of Lower Egypt ; and it must have reached 

 seven or eight hundred feet, before the Pholades bored the rocky 

 shore of the gulf of the delta. 



A flood of light would be thrown on the unwritten history of 

 Egypt by a well-directed and careful re-examination of several points, to 

 some of which I have directed your attention. For example, a single 

 line of borings carried across the middle of the delta down to the solid 

 rock, with a careful record of what is found at successive depths ; a 

 fairly exact survey of the petrified forest, and of the regions in which 

 traces of the ancient miocene sea-shore occur ; a survey of the Selsileh 

 region, with a determination of the heights of the alluvial terraces 

 between this point and Semneh ; and an examination of the contents 

 of the natural caves which are said to occur in the limestone rocks 

 about Cairo and elsewhere would certainly yield results of great im- 

 portance. And it is to be hoped that, before our occupation of the 

 country comes to an end, some of the many competent engineer offi- 

 cers in our army will turn their attention to these matters. 



But, although so many details are still vague and indeterminate, 

 the broad facts of the unwritten history of Egypt are clear enough. 

 The Gulf of Herodotus unquestionably existed and has been filled 

 up in the way he suggested, but at a time so long antecedent to the 

 farthest date to which he permitted his imagination to carry him, 

 that, in relation to it, the historical period, even of Egypt, sinks into 

 insignificance. 



However, we moderns need not stop at the time when the delta 

 w r as a gulf of the sea. The limestone rocks in which it is excavated 

 and which extend east, west, and south for hundreds of miles, are full 

 of the remains of marine animals, and belong, the latest to the eocene, 

 the oldest to the cretaceous formation. The miocene gulf of the delta 

 was, in fact, only the remains of the wide ocean which formerly ex- 

 tended from Hindostan to Morocco ; and at the bottom of which the 



