744 beport — 1884. 



cephalus Matthewi the surface, in the first three stages of growth, appears smooth ; 

 in the fourth, tubercles hegin to appear, and ahout the fifth stage all projecting 

 parts of the test are studded with them. Those on the glabella and frontal lobe 

 are arranged in transverse rows ; those on the cheeks in interrupted rows conform- 

 ing more or less to the periphery of these protuberances. Towards the adult stage 

 these tubercles and spines become more irregular in position and number, conform- 

 ing in this respect to the law of development in the Ammonites, expounded by 

 Professor Alphonso Hyatt. 



3. Report on the Rate of Erosion of the Sea Coasts of England and 



Wales. — See Reports, p. 238. 



4. Fourth Report on the Earthquake Phenomena of Japan. 

 See Reports, p. 241. 



5. The Geology of Palestine. By Professor E. Hull, LL.D., F.R.S. 



See p. 272. 



6. Notes on Niagara. By P. Hallf.tt, M.A. 



These notes may be expressed in abstract in the following propositions, and are 

 submitted to the Section as questions for its consideration. 



1. That, assuming the principle of the gradual formation of the cataract, the 

 condition of existence of the present overhanging precipice is the superimposition 

 of the hard Niagara limestone — corresponding to the Wenlock limestone — upon 

 the friable Niagara shale, the latter being undermined, and the former left over- 

 hanging; that the condition of existence of the rapids above the precipice is the 

 succession of hard rocks simply, and that these differences of condition probably 

 differentiate overhanging Falls from Rapids generally. 



'2. Hence, in case of the precipice receding to a position above the shale, the Fall 

 would disappear and become a Rapid. 



o. lliat the course of the water in the Rapids as an effect of increasing 

 velocity is convergent to mid-channel ; and hence the Rapids, instead of being a 

 source of danger to Goat Island and the small islands in their current, are actually 

 a protection to them by determining the water from their banks. 



4. That the water of the Fall undergoes a continuous disintegration from 

 summit to base, breaking up into smaller and smaller masses and spreading 

 out as it descends. The ' continuous roar ' of Niagara is really a succession of 

 impulses. 



5. That this disintegration is a consequence of the collision between the falling 

 water and the column of air beneath it ; and that the compressed air in its 

 descent is propelled inwards and outwards : inwards forming the well known rush 

 of winds behind the Falls, and driving the heading of excavation in the shale ; 

 outwards sending up the cloud mist that continuously hangs over the Falls. 



6. That this collision between the air and falling water is really a conservative 

 influence, distributing the direct force of the fall and partly transmitting it both 

 directly and by reaction along the currents of the gorge. 



7. That besides the force of the air propelled against the shale face of the 

 precipice as a cause of its excavation, attention is also to be directed to the 

 continuous drainage from the shale, as evidenced by springs, &c. Even along 

 the gorge where there are no falls this appears to determine an undermining action 

 or recession of the banks below, with overhanging rocks above. 



8. That retrocession of the Falls, evident as it is, is not to be regarded as the 

 operation of a mechanical force necessarily continuous, but as a movement to 

 equilibrium. Hardly any retrocession has occurred in parts of the American Fall 

 during the time that the Canadian one has gone back some 500 yards. Retrocession 



