U. S. FLAG-SHIP PAWNEE,

Saint John's River, Fla., February 12, 1864.

Major General Q. A. GILLMORE,

Commanding Dept. of the South, Jacksnville, Fla.:

GENERAL: I have to acknowledge the receipt of your communication* of the 10th instant, and assure you that I had no intention of causing you the least surprise, for the case seemed to me too plain to admit of question, supposing, of course, that I was rightly informed. The premises which have controlled your views differ widely, however, from the report made to me, a copy of which is inclosed herewith. It is a plain narrative and from it you will perceive:

First. That a gun-boat reached the town before the troops landed there on Sunday, the 7th, and proceeded to the creek above on the evening of the same day, in pursuance of orders of the 6th, to prevent the escape of the Saint Mary's therefrom, at which time no troops had left Jacksonville, except a few cavalry to keep off the pickets that had been driven out.

Second. It is stated that the Saint Mary's, on hearing of the arrival of the troops, was preparing to leave the creek and escape up the Saint John's, but finding that she was blockaded by the Norwich returned.

Third. I believe also that the troops did not advance in force before Monday, the 9th, and have not yet been within 3 miles of Cedar Creek. Of this I am not positively informed; you are.

It is evident from the locality and the circumstances that no movement into the interior by your army, or caused the rebels to destroy her. She could not by any possibility, therefore, be your prize, whereas one gun-boats did aactually prevent her escape, and withthe other gun-boats would have captured or destroyed her, even if you had not sent a man into the interior.

While, therefore, I wish not to be understood as undrvaluing the due effect of the result produced by your landing troops in Jacksonville, I do believe that the operations by water were much more material to our possession of the Saint Mary's.

I will insist on whatever may be due to the navy, but there is not the least disposition with me to detract from the army. In my view the Saint Mary's is a capture of the join operation, and as there is both a propriety and convenience in assigning to each branch such property of the rebels, for public use, as may fall into our hands, according to the natur of such property and its obvious uses, no rule could be more conductive to the public interest thatn to let the navy have whatever may belong to the water and the army whatever may belong ashore. For these reasons I claim the Saint Mary's, and hope you will concur with em in the above views.

At the same time, if you do not, permit me to suggest that it would be advisable to raise the vessel before raising any question as to her use by the navy or army.

Finally, if we are unable to concur as to the disposition of the Saint Mary's, a reference to higher authorities should only be made after having agreed on the facts.

I am, very respectfully, your obedient servant,

JOHN A. DAHLGREN,

Rear-Admiral, Commanding South Atlantic Blockading Squadron.

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*Not found.

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