There would be no way that sacrifices could have been carried on land because of all the dead bodies buried on the beaches of the Boucolia. There also would have been no room for a massive structure described in the literature in the Jewish quarter. There was very little available space. So now I am making some inquiries about the technical limitations in the use of Roman concrete. Yes, there was such a thing. An American engineer has set up a website on this very subject. The question of course is whether a concrete foundation could have been poured out at sea.
Of course stones could have laid to make the base or a large existing rock formation could have been used. Interestingly Severus of Al'Ashmunein remembers the location of St. Mark's church as having been established during a return visit to Alexandria after his first visit in a similar local:
Then he returned to Alexandria, and found that the brethren had been strengthened in the faith, and had multiplied by the grace of God, and had found means to build a church in a place called the Cattle-pasture, near the sea, beside a rock from which stone is hewn [History of the Patriarchs 1:2]
This understanding of the Church of St. Mark being BESIDE a great rock might simply represent the location of the basilica NEAR our Jewish holy place. It is worth noting that the Acts of Archelaus features a semi-mythical 'little Mark' (Lat. Marcellus) who is called:
that man of illustrious name, whom he [Mani] endeavoured to turn aside from our doctrine and faith, with the object, to wit, of making him an effective supporter of this impious teaching. Nevertheless, in spite of all his plausible addresses, he failed to move him or turn him aside from the faith in any one particular. For this most devout little Mark was only found to be like the rock on which the house was built with the most solid foundations; and when the rain descended, and the floods and the winds burst in and beat upon that house, it stood firm: for it had been built on the most solid and immoveable foundations.
I have always felt that the figure of 'little Mark' of Osrhoene has been underestimated by scholars. He is undoubtedly (given the provenance) 'Marcion' (Gk 'little Mark') who the Manichaeans argued was a herald of Mani.
This use of Matt 7:24/Luke 6:48 to effectively apply to the 'house' or church of St. Mark fits within a pattern which I think takes us ultimately back to a historical situation early in the second century where a refurbished or re-dedicated Alexandrian temple was devoted to the Evangelist.
Before I hear the objection that the saying doesn't appear in the canonical gospel according to Mark, the reader should be reminded of a pattern within the Alexandrian tradition where Mark is said to have (a) been an eyewitness to every narrative in his gospel, even the Passion but (b) been present in a number of scenes which only appear in other canonical gospels (i.e. the marriage at Cana, the appearance of the risen Christ in the house where the doors were shut).
At the same time Severus of al'Ashmunein references 'sayings' that Jesus said to 'little Mark' or with Mark in mind most notably:
What shall we say the kingdom of God is like, or what parable shall we use to describe it? It is like a mustard seed, which is the smallest seed you plant in the ground. Yet when planted, it grows and becomes the largest of all garden plants, with such big branches that the birds of the air can perch in its shade. [Mark 4:30 - 32]
According to Severus this was said to Mark with the idea that the little disciple would grow into the messiah of Christianity.
The idea then that Jesus should have been referencing the establishment of the Church of St. Mark (or the re-dedication of the Jewish house of God to THE Christian 'church' in Egypt) at Alexandria is highly significant. It follows a pattern that we see emerge from Clement's explanation of the first 'addition' (I would argue in fact that there a number of notable 'subtractions' to make our canonical text) to the Alexandrian gospel of Mark.
In the same way as Clement explains that Mark wrote his gospel by "bringing in certain sayings of which he knew the interpretation would, as a mystagogue, lead the hearers into the innermost sanctuary of that truth hidden by seven veils. Thus, in sum, he prepared matters, neither grudgingly nor incautiously, in my opinion, and, dying, he left his composition to the church in Alexandria, where it even yet is most carefully guarded, being read only to those who are being initiated into the great mysteries" the saying:
He is like a man building a house, who dug down deep and laid the foundation on rock. When a flood came, the torrent struck that house but could not shake it, because it was well built.
was originally YET ANOTHER saying which "led hearers into the innermost sanctuary of that truth hidden by seven veils" - i.e. drew them to the Church of St. Mark in Alexandria.
In other words even though WE THINK of the saying as Matt 7:24/Luke 6:48 in our ROMAN COLLECTION and connect the idea to the Church of St. Peter via the saying:
you are Peter, and on this rock I will build my church, and the gates of Hades will not overcome it. [Matt 16:18]
it is important to note that this saying was unknown to Irenaeus and other of the earliest witnesses. Once again I see the Roman Church removing and 'rebaptizing' sayings from the original (Alexandrian) gospel of Mark which were used to 'draw hearers' TO THE HOLINESS AND THE MYSTERY associated with the same 'Church of St. Mark' in Alexandria, now developed for a counter-dogma relating to the FALSE Church of St. Peter in Rome.
Even Irenaeus' language suggests this 'movement' when he speaks of the coziness with the Emperor Constantine as 'the true Exodus' i.e. the movement of the people of Israel AWAY FROM EGYPT and the Alexandrian tradition [AH iv. 30]
I am in a bit of rush but I want to remind readers that SOMETHING about the Jewish quarters was causing Apion to see a similar image when he speaks of the Jews as
coming out of Syria, and inhabited near the tempestuous sea, and were in the neighborhood of the dashing of the waves [Against Apion 2]
There are no great waves on Chatby beach today. It is calm like much of the Mediterranean. I imagine that the image was conjured owing to the fact that a rock which is either no longer visible (owing to rising sea levels along the shore) was 'causing' this image of 'dashing waves' and a 'tempestuous sea.'
More to follow ...
UPDATE 1 Consider also the description of 'little Mark' AS the rock dashed by waves in other parts of the Acts of Archelaus:
for through that whole territory the fame of the piety of little Mark spread so grandly, that large numbers of men belonging to various cities were inflamed with the intensest desire to see and become acquainted with the man, and most especially those persons who had not had occasion to bear penury before—to all of whom this remarkable man, following the example of a little Mark of old, furnished aid most indulgently, so that they all declared that there was no one of more illustrious piety than this man. Yea, all the widows, too, who were believers in the Lord had recourse to him, while the imbecile also could reckon on obtaining at his hand most certain help to meet their circumstances; and the orphaned, in like manner, were all supported by him, so that his house was declared to be the hospice for the stranger and the indigent. And above all this, he retained in a remarkable and singular measure his devotion to the faith, building up his own heart upon the rock that shall not be moved. [ibid 2]
