Weno and Pawpaw Formations 6i) 



AMMONITES 1 



HAMITES TENAWA Adkins and Winton 



1920: Hamites tenawa Adkins and Winton, Univ. Texas Bull. 1945, p. 43, pi. 6, fig. 4. 

 1920: Hamites tenawa Winton and Adkins, Univ. Texas Bull. 1931, p. 21. 

 1920: Hamites sp., Winton and Adkins, ibid., p. 69. 



HORIZON: Pawpaw formation, clay fades, base. 



LOCALITY : About three miles southeast of Haslet, Tarrant County, 

 Texas (type locality); 714, near Fort Worth, Texas; 723, Glen Garden 

 Country Club, near Fort Worth, Texas. 



Among several Hamites in the Pawpaw clay is a straight equal ribbed 

 species resembling Hamites simplex. The species and its suture have 

 been figured elsewhere; the suture has six lobes and six saddles, mainly 

 bifid and slightly dissected. 



HAMITES sp. aff. ARMATUS Sowerby 



HORIZON: Base of the Pawpaw formation, clay facies. 



LOCALITY : 714, near Fort Worth, Texas. 



Fragments of a small Hamites preserved in hematite and showing on 

 every second or third rib lour tubercles, two lateral and two ventral, are 

 found in the basal third of the Pawpaw clay. The suture is rather similai 

 to that of Hamites armatus Sowerby and has the following characteris- 

 tics : Suture consists on each side of three saddles and two lobes, in ad- 

 dition to the siphonal and antisiphonal lobes ; suture much more dissected 

 than that of Hamites tenawa; siphonal saddle narrow and low, with three; 

 rounded subdivisions; siphonal lobe narrow, bifid, each lobule narrow at 

 base, trifid terminally; first lateral saddle longer and much broader than 

 siphonal lobe, flared terminally, bifid, each division twice bifid and laterally 



'In coiled ammonites the external margin of the volution (often keeled) is ventral 

 and the internal, concealed margin is dorsal; the sides of the volution are the flanks, 

 the terminal opening is the aperture. Lobes point backwards, away from the aperture, 

 and saddles forwards, toward the aperture. The siphonal (external, ventral) lobe lies 

 on the ventral mid-line and its angulated lobules point backwards; the antisiphonal 

 lobe lies on the dorsal mid-line and its lobules point backwards. Next to the siphonal 

 lobe and on each side of it is the first lateral saddle, and dorsal to it the first lateral 

 lobe ; still more dorsally the second lateral saddle, then the* second lateral lobe. Further 

 saddles and lobes are numbered seriatim and are often called adventitive elements. 

 In straight shells (Hamites, Baculites, Ptychoceras, straight portions of Scaphites) 

 and in fragments of Turrilites, the siphuncle should first be located; the siphonal lobe 

 lies upon it. 



