writing to replace him with another supervisor. The Engineer shall not be required to give any reason for such removal of supervisor or other worker he may from time to time require. 

• xii. The supervisor shall not be changed except with the consent of the Engineer unless the supervisor proves to be unsatisfactory to the Contractor and ceases to be in his employ. The supervisor shall represent the Contractor in his absence and directions on matters given to him shall be held to be given to the Contractor. The Contractor shall give efficient supervision to the work using his best skill and attention at all times.
  
  
• xiii. During the construction of work which the Engineer considers it necessary, the Contractor shall employ on the work a responsible experienced Professional Engineer to generally supervise any supervisor or worker.
  
  
• xiv. The Contractor shall, at no additional cost to the Corporation, furnish all reasonable aid, facilities and assistance required by the Engineer for the proper inspection and examination of the Work or the taking of measurements for the purpose of payment.
  
  
• xv. Where the Contractor finds any errors, inconsistency or omission relating to the Contract, the Contractor shall promptly report it to the Engineer and shall not proceed with the activity affected until receiving direction from the Engineer.
  
  
• xvi. The Contractor shall promptly notify the Engineer in writing if the subsurface conditions observed in the Working Area differ materially from those indicated in the Contract Documents.
  
  
• xvii. The Contractor shall, if required by the Engineer in writing, search for the cause of any defect, imperfection, or fault under the directions of the Engineer, and the cost of the work carried out in searching as aforesaid shall be borne by the Contractor, and he shall repair, rectify, and make good such defects, imperfections, or defaults at his own expense.
  
  
• xviii. The Contractor shall arrange with the appropriate utility authorities for the stakeout of all underground utilities and service connections which may be affected by the Work. The Contractor shall be responsible for any damage done to the underground utilities by the Contractor's forces during construction. The Contractor shall be responsible for any damage done to the private service connections.