APPENDIX B. 313 



as, in the opinion of the Engineer, shall be suitable for this purpose. Where so directed, 

 the material shall be moistened and rammed in place as the filling progresses. 



The embankment or back fill behind the land-wall of the lock on which the paving 

 is to be placed must be made during the first working season to the height of the land- 

 wall as then built, if any of the latter is in place. If deemed necessary by the Engi- 

 neer, riprap shall be placed on the fill to a depth of about i foot to protect it during 

 the winter and spring rises, payment being made for this as "Riprap." 



The paving itself shall in no case be placed until the completed embankment and 

 back fill have been subject to the exposure of one winter's floods and spring rains. 

 Any additional filling to be made after such exposure shall be thoroughly well rammed 

 to the satisfaction of the Engineer. 



To allow for shrinkage the final measurement will not be made until two months 

 after the completion of the embankment. 



26. Paving.* The space behind the land-wall and between the wing-walls, to a 

 distance of about .... feet from the chamber face shall be covered with stone paving, 



with a curb wall 12" wide along the back and at each end, of a depth of feet. Every 



stone so used shall have upper surface dimensions of at least The stone 



shall be sound, and well shaped, laid with joints not exceeding f of an inch, and all 

 joints must be grouted with three to one cement mortar to a depth of 2 inches. 

 No variation of more than i inch from the grade line will be permitted. The stones 

 shall have a depth of 10 to 12 inches, and shall be placed on a bed of spalls or river 

 gravel 6 inches in depth, laid on the graded and rammed surface of the earth. The 

 entire surface must be set to the lines and slopes given by the Engineer. The price bid 

 per square yard for paving must include the cost of furnishing and placing the bed of 

 spalls or gravel upon which it is laid, and the grouting of the joints. None of this 

 paving and curbing shall be laid until the embankment shall have settled sufficiently 

 for the purpose, as specified in the preceding paragraph. The paving and curb-walls 

 will be estimated per square yard. 



(Note. If concrete paving is to be used in place of the above, which is common 

 or rough-dressed paving, the following may be substituted for the first few sentences. 



Paving shall be of cement concrete, well-rammed and faced as described for 

 the coping. It shall be 6" in total thickness, and shall be similarly laid by expe- 

 rienced sidewalk masons and be divided into rectangular blocks as shown on the 

 drawings. Curb-walls to be paid for as " Paving," and of the same material as the pav- 

 ing, 1 2 inches wide and 2 feet deep, with rounded top, 2 inches above the paving, shall 

 be laid along the back edge of the paving and along the sides to meet the wing-walls. 

 Before laying the paving and curb-walls, the earth embankment underneath shall be 

 rammed and graded carefully to 6 inches below the bottom of the concrete, then a bed 

 of spalls or gravel shall be laid, rammed, and graded on the earth, of sufficient depth 



* This clause may be extended to include paving the banks above ana below the land-wall, where such 

 is desired. 



