TRANSACTIONS OF THE SECTIONS. 73 
3. The old wall of the quay was discovered, which in the year 1750 was buried 
under the rubbish originating from the destruction by fire of the cathedral. A small 
stair descended from this wall to the Rhine ; the two uppermost of these bore signs 
of having been much trodden; the third appeared to have been less so, while the 
lower one showed no injury from the impress of the foot. 
4, In the neighbourhood of the St. Signaticus Church, a small brook, the Filgback, 
flowed in the eleventh century into the Rhine, at a level six feet lower than it does 
at present. The lately-discovered remains of buildings, which enclosed the sandy bed 
of this little brook, give evidence of that period. The average level of the waters of 
the Rhine at Mayence has been long held as being five feet above the zero of the 
Pegel there. [By Pegel is meant a fixed point taken about a hundred years ago, as 
being at that time, and indeed since, a mark of the depth of the water, and therefore 
a guide to the boatman.] In the year 1750, the point of this Pegel, and at the same 
time the mean level of the waters of the Rhine, were 88. inches deeper than now, 
which agrees tolerably well with the half-trodden condition of the descending stairs 
just mentioned. 
It is not to be supposed that the body of water in the Rhine has since then in- 
creased ; but the increased height of its waters may be naturally accounted for by 
the facts just mentioned, which show the increasing height of the level of its bed. 
This height increases, according to these facts, 83 inches in a century. 
We therefore arrive at the following figures :— 
Eng. ft. in 
The Rhine in 1050 ...... 13 4 
17γὅ0 ...... 5 9 
1860 ...... 0 88 inches deeper than in | a.p. 
These standards seem to agree together, as the remains of Roman structures in 
the neighbourhood of the water are to be found thirteen feet under the mean level 
of the streets, and are not found higher. Again, the ruined basements (in architec- 
tural terms ‘‘socle”) of buildings of later centuries are found less and less deep as 
» the date of their creation comes nearer and nearer to the present century. 
᾿ To suppose that the bed of the river has not become considerably higher, would be 
to conclude that the architects of earlier times were far from what we are accustomed 
to believe of them, A foundation for the Fish-gate could hardly have been attained 
even with the water at its present middle height ; whilst we further notice, that on 
occasion of a very moderate increase of water, the lower part of the town would have 
been wholly overflowed. The rings set in for the purpose of securing the boats, and 
even the architectural ornaments, would only have been seen and available when the 
water was accidentally at the lowest. But, in a word, the bed of the river Aas risen, 
and man has been obliged to evade the progress of the waters by raising from time to 
time the surface of the bordering lands. 
If, then, the surface of the river-bed does become elevated, and in the proporticn 
of 83 inches every century, the protecting dams must be made to rise in the same 
proportion. The surrounding grounds cannot, however, rise in that proportion, and 
it consequently occurs, that land under cultivation lies lower than the water, and 
therefore, in case of flood, is the more exposed to danger, should the defensive dams 
be broken down. 
Remarks as to the earlier Existence of the Binnen or Inland Lake. 
By Dr. Lupwic Becker. 
In the year 1846, some buildings were undertaken in Mayence on the spot where 
an ancient Roman castle formerly stood. For this purpose the side of a sloping 
hill had to be lowered. The formation I found to be of the more modern tertiary 
chalk, At the depth of fifty feet I found innumerable remains of fishes in a stratum 
of clay. Agassiz travelled with me about this time, being on his way to North 
America, and I let him sce these fossils. He recognized amongst others, a Perca, to 
which Herr Von Meyer gave the name of Perca Moguntina. 1 also found fragments 
of Crocodiles, Tortoises, Microtherium, &c. At the depth of fifty feet there is a 
great deposit of plastic clay, over which are broken strata of chalk and Paludine. 
The surface-water, which had easily found its way down to these, had given the clay 
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