<HTML>Elizabeth,
Perhaps the most comprehensive examination of ALL the data involved is in Colin Reader's most recent paper, from 2003.
However, you can read it's outdated (yet still essentially correct) predecessor on line at Ian Lawton's site.
<center><a href="[
www.ianlawton.com] Knew the Sphinx</a></center>.
<blockquote>
...The strata exposed at the Sphinx have been divided into three members. The lowest, Member I, consists of a massive and durable reefal limestone, exposed across much of the base of the Sphinx enclosure. The lowest lying parts of both the body of the Sphinx and the western exposures consist of Member I strata, with the quarried height increasing up-dip, towards the north west. The entire northern exposure consists of Member I limestones.
The upper body of the Sphinx and the upper part of the adjacent exposures to the south and west, consist of the overlying Member II strata, a cyclothemic series of seven fine grained limestone units which, generally, become more durable towards the top of the sequence. Of these seven units, units 1 to 6 have been further divided into two sub-units, the lowest of which consists of a less durable, marly rock and is identified by the Roman numeral i. The upper more durable sub-unit is identified by the Roman numeral ii.
The head and neck of the Sphinx are carved from perhaps the only Member III exposure at Giza6 which, on the basis of durability, has also been divided into two sub-units. The neck of the Sphinx consists of relatively less durable rocks, whereas, the head has been carved from one of the most durable units of the Upper Mokattam formation (the durability of the Member III strata has been cited by others to explain the remarkable preservation of the Sphinx's face and Nemes head-dress). </blockquote>
His new paper includes even more data and evidence, with excellent photographs that clearly demonstrate the validity of his claims. (although the conclusion is still being debated actively).
Here's an illustration that is very similar to one in Lehner's "The Complete Pyramids". This one, however, is from Davidovits' site, and the slope is rather exaggerated.
<center><img src="[
www.geopolymer.org];
I hope this helps.
Anthony</HTML>
![www.geopolymer.org](http://www.geopolymer.org/images/GeolGiza.gif"></center>){kind=link}