Public Sub FindM()
     Dim vData As Variant
     Dim rowMax As Date, minInMax As Date
     Dim iRow As Long, iCol As Long
     vData = ActiveSheet.UsedRange.Value
     For iRow = 1 To UBound(vData)
         rowMax = 0
         For iCol = 1 To UBound(vData, 2)
             If IsDate(vData(iRow, iCol)) Then
                 If vData(iRow, iCol) > rowMax Then rowMax = vData(iRow, iCol)
             End If
         Next
         If (minInMax = 0) And (rowMax > 0) Then
             minInMax = rowMax
         ElseIf (minInMax > 0) And (rowMax > 0) Then
             If minInMax > rowMax Then minInMax = rowMax
         End If
     Next
     Debug.Print minInMax
End Sub

Public Function MinInMaximun(ByVal vData As Variant) As Date
     Dim rowMax As Date, curMax As Date
     Dim iRow As Long, iCol As Long
     curMax = DateSerial(2300, 12, 31)
     For iRow = 1 To UBound(vData)
         rowMax = 0
         For iCol = 1 To UBound(vData, 2)
             If IsDate(vData(iRow, iCol)) Then
                 If vData(iRow, iCol) > rowMax Then rowMax = vData(iRow, iCol)
             End If
         Next
         If curMax > rowMax Then curMax = rowMax
     Next
     MinInMaximun = curMax
End Function

Sub qq()
    Dim i&, k&, min&, s&
    s = 6 'строка начала блока
    k = Cells(s, Columns.Count).End(xlToLeft).Column 'последняя колонка 1-й строки
    min = Cells(s, k)
    For i = s + 1 To Range("A" & Rows.Count).End(xlUp).Row
       k = Cells(i, Columns.Count).End(xlToLeft).Column
       If Cells(i, k) < min Then min = Cells(i, k)
    Next
    MsgBox min & "   в дату сам переведи."
End Sub