SAVI ON THE MONTI PISANI. 5 



successively deposited at the bottom of the same ocean, without any 

 interruption ; although it may be more difficult to determine this 

 point with respect to the verrucano on account of the greater amount 

 of disturbance which it has undergone. 



In discussing the evidence derived from organic remains, both 

 animal and vegetable, after having noticed the different genera 

 (p. 48) which occur in the various formations from the alberese 

 which contains small Nummulites, several species of foraminifera, and 

 various echinoderms resembling Spatangus, down to the verrucano 

 in which no organic remains have hitherto been found, the author 

 comes to the following conclusions (p. 50): — 



1. That the fucoids are the prevailing fossils in the secondary 

 formations, overlying the dark grey limestone with flints. 



2. That the Ammonites characterize this limestone as well as the 

 red variety underlying and connected with it. They are more abun- 

 dant in the latter bed, and are accompanied by numerous fragments 

 of Apiocrinites. 



3. That in the inferior limestones without flints, bivalves and tur- 

 riculated fossils occur with the remains of zoophytes as in those of 

 La Spezzia. 



4. That below these limestones all organic remains disappear. 



He then proceeds to establish a comparison between the forma- 

 tions of the Pisan hills and those of the N.W. of Europe, in order to 

 determine with which of the latter the former correspond. For this 

 purpose he considers the red ammonite limestone which extends 

 into Lombardy as the best base-line. This appears, in the first 

 instance, from the fossil evidence of the Ammonites, to belong to 

 the lias ; but Leop, v. Buch has referred it to the upper Jurassic 

 formation, and with this opinion the author finally agrees, although 

 the beds certainly contain lias fossils, and do not contain all those 

 which are found in Lombardy, The light grey limestone with flint 



coverlying the red is also referred to the same age. 



The limestones below the red ammonite limestone, containing 

 bivalves and univalves. Ammonites and Pentacrinites, are referred 

 to the lias. The verrucano, although containing no fossils, is con- 

 sidered from its geological character as a continuation of the lias 

 formation. 



No animal remains are found in the deposits which overlie the 

 red ammonite limestone; vegetable remains alone must therefore 

 be referred to, particularly fucoids (amongst which 7^. targioni is 

 most abundant) ; and after various arguments the author concludes 

 by referring to the cretaceous series all the formations from the 

 light grey limestone with flints, immediately overlying the red 

 ammonite limestone, up to the alberese inclusively ; they all con- 

 tain fucoids; there is a total absence of fossils, either more ancient 

 or more recent than the chalk ; and they are all united by mine- 

 ralogical transition as well as by conformability of stratification. 

 But these same reasons tend to unite in the same series the last or 

 overlying deposit, perfectly connected with the macigno in many 

 parts of Tuscany, and containing several broken bauds full of small 



