Mr. Gardner on the Existence of Chalk in Brazil. 149 



The top is perfectly level, forming what the Brazilians call Taboleiras. 

 At Villa do Crato, a rather large town, situated at the base of an 

 eastern branch of the range, called the Serra de Araripe, I remained 

 several months in the latter end of 1838 and beginning of 1839, and 

 consequently had ample opportunities for studying not only the Botany, 

 but the Geology of that region. Shortly after I arrived there, I sent 

 home part of the collection of fossil fishes which is now before us, to 

 the care of my much lamented friend, the late J. E. Bowman, Esq., 

 of Manchester. They were exhibited by him at the Meeting of the 

 British Association at Glasgow ; and a short notice which accompanied 

 them, giving some account of the circumstances under which they 

 were found, was read by him, and afterwards published in the Edin- 

 burgh New Philosophical Journal for Jan. 1841. My journeyings and 

 observations after these had been despatched, enabled me to deter- 

 mine much more accurately the nature of the formation to which they 

 belong. 



• The great mass of this elevated table land consists of a very soft, 

 whitish, yellowish, or reddish coloured sandstone, which in many places 

 must be more than 600 feet thick ; and it is in this rock that the fossil 

 fishes are contained. The first thing which led me to suspect that 

 this rock belonged to the chalk formation, was an immense accumula- 

 tion of flints and septaria, similar to those of the chalk of England, 

 which I found on the acclivity of the range during a journey made 

 along its base to the north of Crato. I now began to inquire if any 

 thing like chalk was to be found in the neighbourhood, and was 

 informed that several pits occurred on the Serra, from whence the 

 inhabitants obtained it for the purpose of white-washing their houses. 

 These pits I afterwards found to be situated in a deep layer of red 

 coloured diluvial clay, which is found immediately over the sandstone 

 of the Serra. In a ravine, near Crato, I endeavoured to ascertain on 

 what rock the sandstone rested, and found it to consist of several 

 layers of more or less compact limestones and marls, with a bed of 

 lignite about two feet thick. What these rested on, I could not at 

 that time ascertain, but some time afterwards when I crossed to the 

 west side of the range, I found these limestones to rest upon a deposit 

 of very dark-red coarse-grained sandstone, abounding in small nodules 

 of ironstone. Thus, then, we find, that the structure of the rocks 

 in this locality are very similar to those of the chalk formation in 

 England. There is 



Ist. A ferruginous sandstone deposit, equivalent to the lower green 

 sand or Shankland sand, a, in the cut, resting on clay slate s. 



